%%
@misc{fds348022,
Author = {S. Haravifard},
Title = {A Super (Lattice) Surprise},
Journal = {Fields Magazine, National High Magnetic Field
Laboratory},
Year = {2019},
url = {https://nationalmaglab.org/fieldsmagazine/archives/a-super-lattice-surprise},
Key = {fds348022}
}
@article{fds374151,
Author = {Bag, R and Dissanayake, SE and Yan, H and Shi, Z and Graf, D and Choi, ES and Marjerrison, C and Lang, F and Lancaster, T and Qiu, Y and Chen, W and Blundell, SJ and Nevidomskyy, AH and Haravifard,
S},
Title = {Beyond Single Tetrahedron Physics of Breathing Pyrochlore
Compound Ba3Yb2Zn5O11},
Year = {2022},
Month = {October},
Key = {fds374151}
}
@article{fds368671,
Author = {Bag, R. and Dissanayake, S.E. and Yan, H. and Shi, Z. and Graf, D. and Choi, E.S. and Marjerrison, C. and Lang, F. and Lancaster, T. and Blundell, S.J. and Nevidomskyy, A.H. and Haravifard, S.},
Title = {Beyond Single Tetrahedron Physics of Breathing Pyrochlore
Compound Ba3Yb2Zn5O11},
Journal = {Physical Review Letters},
Year = {2022},
Key = {fds368671}
}
@article{fds375121,
Author = {Bag, R and Dissanayake, SE and Yan, H and Shi, Z and Graf, D and Choi, ES and Marjerrison, C and Lang, F and Lancaster, T and Qiu, Y and Chen, W and Blundell, SJ and Nevidomskyy, AH and Haravifard,
S},
Title = {Beyond single tetrahedron physics of the breathing
pyrochlore compound Ba3Yb2Zn5 O11},
Journal = {Physical Review B},
Volume = {107},
Number = {14},
Pages = {P.L140408},
Year = {2023},
Month = {April},
url = {http://dx.doi.org/10.1103/PhysRevB.107.L140408},
Abstract = {Recently, a new class of quantum magnets, the so-called
breathing pyrochlore spin systems, have attracted much
attention due to their potential to host exotic emergent
phenomena. Here, we present magnetometry, heat capacity,
thermal conductivity, muon-spin relaxation, and polarized
inelastic neutron scattering measurements performed on
high-quality single crystal samples of the breathing
pyrochlore compound Ba3Yb2Zn5O11. We interpret these results
using a simplified toy model and provide insight into the
low-energy physics of this system beyond the single
tetrahedron physics proposed previously.},
Doi = {10.1103/PhysRevB.107.L140408},
Key = {fds375121}
}
@article{fds302508,
Author = {Haravifard, S and Fritsch, K and Asano, T and Clancy, JP and Yamani, Z and Ehlers, G and Nishimura, T and Inagaki, Y and Kawae, T and Swainson, I and Gaulin, BD},
Title = {Coexistence of singlet and ordered S=12 moments in the
ground state of the triclinic quantum magnet
CuMoO4},
Journal = {Physical Review B - Condensed Matter and Materials
Physics},
Volume = {84},
Number = {9},
Publisher = {American Physical Society (APS)},
Year = {2011},
Month = {September},
ISSN = {1098-0121},
url = {http://dx.doi.org/10.1103/PhysRevB.84.094436},
Abstract = {CuMoO4 is a triclinic quantum magnet based on S=1/2 moments
at the Cu2+ site. It has recently attracted interest due to
the remarkable changes in its chromic and volumetric
properties at high temperatures and in its magnetic
properties at low temperatures. This material exhibits a
first-order structural phase transition at TC ∼ 190 K as
well as a magnetic phase transition at TN ∼ 1.75 K. We
report low-temperature heat capacity measurements as well as
extensive elastic and inelastic neutron scattering
measurements on powder samples taken above and below TN. We
observe neutron diffraction consistent with a simple (1/2,
0, 0) antiferromagnetic structure indicating a doubling of
the a-axis periodicity below TN. In addition, inelastic
neutron scattering above a spin gap of ∼2.3 meV is
consistent with triplet excitations out of paired S=1/2
moments which form singlet dimers. Low-lying spin wave
excitations are also observed and these originate from
ordered S=1/2 moments below T N. Taken together these
measurements show the ground state of CuMoO4 to display both
nonmagnetic singlets and ferromagnetically coupled spins
coexisting within an antiferromagnetic structure below T N
∼ 1.75 K. © 2011 American Physical Society.},
Doi = {10.1103/PhysRevB.84.094436},
Key = {fds302508}
}
@article{fds361373,
Author = {S. Haravifard and Steinhardt, WM and Shi, Z and Samarakoon, A and Dissanayake, S and Graf,
D and Liu, Y and Zhu, W and Marjerrison, C and Batista, CD and Haravifard,
S},
Title = {Constraining the Parameter Space of a Quantum Spin Liquid
Candidate in Applied Field with Iterative
Optimization},
Journal = {Phys. Rev. Research},
Volume = {3},
Pages = {033050},
Year = {2019},
Month = {February},
Abstract = {The quantum spin liquid (QSL) state is an exotic state of
matter featuring a high degree of entanglement and lack of
long-range magnetic order in the zero-temperature limit. The
triangular antiferromagnet YbMgGaO4 is a candidate QSL host,
and precise determination of the Hamiltonian parameters is
critical to understanding the nature of the possible ground
states. However, the presence of chemical disorder has made
directly measuring these parameters challenging. Here we
report neutron scattering and magnetic susceptibility
measurements covering a broad range of applied magnetic
field at low temperature. Our data shows a field-induced
crossover in YbMgGaO4, which we reproduce with complementary
classical Monte Carlo and Density Matrix Renormalization
Group simulations. Neutron scattering data above and below
the crossover reveal a shift in scattering intensity from M
to K points and, collectively, our measurements provide
essential characteristics of the phase crossover that we
employ to strictly constrain proposed magnetic Hamiltonian
parameters despite the chemical disorder. Constrained
exchange parameters further suggest the material's proximity
to the QSL state in the clean limit. More broadly, our
approach demonstrates a means of pursuing QSL candidates
where Hamiltonian parameters might otherwise be obscured by
disorder.},
Key = {fds361373}
}
@article{fds360533,
Author = {Steinhardt, W. and Shi, Z. and Samarakoon, A. and Dissanayake, S. and Graf, D. and Liu, Y. and Zhu, W. and Marjerrison, C. and Batista, C.D. and Haravifard, S.},
Title = {Constraining the parameter space of a quantum spin liquid
candidate in applied field with iterative
optimization.},
Journal = {Physical Review Research},
Volume = {3},
Number = {3},
Pages = {033050},
Year = {2021},
Key = {fds360533}
}
@article{fds302512,
Author = {Haravifard, S and Banerjee, A and Lang, JC and Srajer, G and Silevitch,
DM and Gaulin, BD and Dabkowska, HA and Rosenbaum,
TF},
Title = {Continuous and discontinuous quantum phase transitions in a
model two-dimensional magnet.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {109},
Number = {7},
Pages = {2286-2289},
Year = {2012},
Month = {February},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.1114464109},
Abstract = {The Shasty-Sutherland model, which consists of a set of spin
1/2 dimers on a 2D square lattice, is simple and soluble but
captures a central theme of condensed matter physics by
sitting precariously on the quantum edge between isolated,
gapped excitations and collective, ordered ground states. We
compress the model Shastry-Sutherland material,
SrCu(2)(BO(3))(2), in a diamond anvil cell at cryogenic
temperatures to continuously tune the coupling energies and
induce changes in state. High-resolution X-ray measurements
exploit what emerges as a remarkably strong spin-lattice
coupling to both monitor the magnetic behavior and the
absence or presence of structural discontinuities. In the
low-pressure spin-singlet regime, the onset of magnetism
results in an expansion of the lattice with decreasing
temperature, which permits a determination of the
pressure-dependent energy gap and the almost isotropic
spin-lattice coupling energies. The singlet-triplet gap
energy is suppressed continuously with increasing pressure,
vanishing completely by 2 GPa. This continuous quantum phase
transition is followed by a structural distortion at higher
pressure.},
Doi = {10.1073/pnas.1114464109},
Key = {fds302512}
}
@article{fds302505,
Author = {Dabkowska, HA and Dabkowski, AB and Luke, GM and Dunsiger, SR and Haravifard, S and Cecchinel, M and Gaulin, BD},
Title = {Crystal growth and magnetic behaviour of pure and doped
SrCu2(11BO3)2},
Journal = {Journal of Crystal Growth},
Volume = {306},
Number = {1},
Pages = {123-128},
Publisher = {Elsevier BV},
Year = {2007},
Month = {August},
ISSN = {0022-0248},
url = {http://dx.doi.org/10.1016/j.jcrysgro.2007.04.040},
Abstract = {High quality single crystals of incongruently melting
SrCu2(BO3)2, both pure and doped with Mg, La and Na have
been grown by optical floating zone (OFZ)-image furnace
technique using self-flux. The obtained single crystals were
characterized by X-ray powder diffraction and by neutron
scattering using highly enriched 11B for selected crystals.
Magnetic susceptibility measurements from 3 to 300 K, with a
magnetic field parallel to the ab plane were performed on
pure and doped crystals oriented by the Laue method. The
measurements show a relatively complex behaviour and confirm
the formation of a spin singlet ground state at low
temperatures. No evidence of superconductivity is observed.
© 2007 Elsevier B.V. All rights reserved.},
Doi = {10.1016/j.jcrysgro.2007.04.040},
Key = {fds302505}
}
@article{fds318450,
Author = {Haravifard, S and Graf, D and Feiguin, AE and Batista, CD and Lang, JC and Silevitch, DM and Srajer, G and Gaulin, BD and Dabkowska, HA and Rosenbaum, TF},
Title = {Crystallization of spin superlattices with pressure and
field in the layered magnet SrCu2(BO3)2.},
Journal = {Nature communications},
Volume = {7},
Pages = {11956},
Year = {2016},
Month = {June},
url = {http://dx.doi.org/10.1038/ncomms11956},
Abstract = {An exact mapping between quantum spins and boson gases
provides fresh approaches to the creation of quantum
condensates and crystals. Here we report on magnetization
measurements on the dimerized quantum magnet SrCu2(BO3)2 at
cryogenic temperatures and through a quantum-phase
transition that demonstrate the emergence of fractionally
filled bosonic crystals in mesoscopic patterns, specified by
a sequence of magnetization plateaus. We apply tens of
Teslas of magnetic field to tune the density of bosons and
gigapascals of hydrostatic pressure to regulate the
underlying interactions. Simulations help parse the balance
between energy and geometry in the emergent spin
superlattices. The magnetic crystallites are the end result
of a progression from a direct product of singlet states in
each short dimer at zero field to preferred filling
fractions of spin-triplet bosons in each dimer at large
magnetic field, enriching the known possibilities for
collective states in both quantum spin and atomic
systems.},
Doi = {10.1038/ncomms11956},
Key = {fds318450}
}
@article{fds348021,
Author = {S. J. Kuhn and Zhenzhong Shi and F. Flicker and T. Helm and J. Lee and William Steinhardt and Sachith Dissanayake and D. Graf and J. Ruff and G. Fabbris and D. Haskel and S. Haravifard},
Title = {Direct observation of an incommensurate two-dimensional
checkerboard charge density wave in the superconductor
Ta4Pd3Te16},
Journal = {Submitted to Proceeding of National Academy of Sciences
USA},
Year = {2019},
Abstract = {We report the observation of a highly unusual incommensurate
twodimensional checkerboard charge density wave (CDW) in the
superconductor Ta4Pd3Te16, using synchrotron X-ray
diffraction. We observe two CDW wavevectors, related by a
crystal symmetry, developing below 16 K at ambient pressure.
The wavevectors, which remain incommensurate at all observed
temperatures, lie neither within the quasi-one-dimensional
(Q1D) chains nor the Q2D planes in which the chains reside
in this monoclinic crystal structure. The bulk CDW
wavevectors are shown to reconcile previous scanning
tunneling microscopy and transport studies. We also
conducted de Haas-van Alphen (dHvA) quantum oscillation
measurements and found no evidence of Fermi surface
reconstruction through the CDW transition, suggesting a very
subtle gap opening. We determine the temperature-pressure
(T-P) phase diagram, and find the superconductivity (SC)
dome to be centered at the pressure where the CDW
instability vanishes, suggesting that the SC in Ta4Pd3Te16
could have its origin in a CDW quantum critical point,
reminiscent of the observations in many unconventional
superconductors. With a thorough comparison to other CDW
materials, we conclude that Ta4Pd3Te16 is a unique CDW
system that features a mixed character of Q1D, Q2D, and
3D.},
Key = {fds348021}
}
@article{fds363187,
Author = {Shi, Z and Dissanayake, S and Corboz, P and Steinhardt, W and Graf, D and Silevitch, DM and Dabkowska, HA and Rosenbaum, TF and Mila, F and Haravifard, S},
Title = {Discovery of quantum phases in the Shastry-Sutherland
compound SrCu2(BO3)2 under
extreme conditions of field and pressure.},
Journal = {Nature communications},
Volume = {13},
Number = {1},
Pages = {2301},
Year = {2022},
Month = {April},
url = {http://dx.doi.org/10.1038/s41467-022-30036-w},
Abstract = {The 2-dimensional layered oxide material
SrCu<sub>2</sub>(BO<sub>3</sub>)<sub>2</sub>, long studied
as a realization of the Shastry-Sutherland spin topology,
exhibits a range of intriguing physics as a function of both
hydrostatic pressure and magnetic field, with a still
debated intermediate plaquette phase appearing at
approximately 20 kbar and a possible deconfined critical
point at higher pressure. Here, we employ a tunnel diode
oscillator (TDO) technique to probe the behavior in the
combined extreme conditions of high pressure, high magnetic
field, and low temperature. We reveal an extensive phase
space consisting of multiple magnetic analogs of the elusive
supersolid phase and a magnetization plateau. In particular,
a 10 × 2 supersolid and a 1/5 plateau, identified by
infinite Projected Entangled Pair States (iPEPS)
calculations, are found to rely on the presence of both
magnetic and non-magnetic particles in the sea of dimer
singlets. These states are best understood as descendants of
the full-plaquette phase, the leading candidate for the
intermediate phase of SrCu<sub>2</sub>(BO<sub>3</sub>)<sub>2</sub>.},
Doi = {10.1038/s41467-022-30036-w},
Key = {fds363187}
}
@article{fds360535,
Author = {Shi, Z. and Dissanayake, S.E. and Corboz, P. and Steinhardt, W. and Graf, D. and Silevitch, D.M. and Dabkowska, H. and Rosenbaum, T.F. and Mila, F. and Haravifard, S.},
Title = {Discovery of unexpected quantum phases in the
Shastry-Sutherland compound SrCu2(BO3)2 under combined
extreme conditions of field and pressure},
Journal = {Nature Communications},
Year = {2021},
Key = {fds360535}
}
@article{fds348015,
Author = {Rutherford, M and Mauws, C and Haravifard, S and Marjerrison, C and Luke, G and Beare, J and Herbert, D and Ritch, J and Wiebe,
C},
Title = {Dy2ScNbO7: an unconventional spin
ice?},
Journal = {Acta Crystallographica Section A Foundations and
Advances},
Volume = {74},
Number = {a1},
Pages = {a172-a172},
Publisher = {International Union of Crystallography (IUCr)},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1107/s0108767318098276},
Doi = {10.1107/s0108767318098276},
Key = {fds348015}
}
@article{fds302511,
Author = {Haravifard, S and Banerjee, A and van Wezel, J and Silevitch, DM and dos
Santos, AM and Lang, JC and Kermarrec, E and Srajer, G and Gaulin, BD and Molaison, JJ and Dabkowska, HA and Rosenbaum, TF},
Title = {Emergence of long-range order in sheets of magnetic
dimers.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {111},
Number = {40},
Pages = {14372-14377},
Year = {2014},
Month = {October},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.1413318111},
Abstract = {Quantum spins placed on the corners of a square lattice can
dimerize and form singlets, which then can be transformed
into a magnetic state as the interactions between dimers
increase beyond threshold. This is a strictly 2D transition
in theory, but real-world materials often need the third
dimension to stabilize long-range order. We use high
pressures to convert sheets of Cu(2+) spin 1/2 dimers from
local singlets to global antiferromagnet in the model system
SrCu2(BO3)2. Single-crystal neutron diffraction measurements
at pressures above 5 GPa provide a direct signature of the
antiferromagnetic ordered state, whereas high-resolution
neutron powder and X-ray diffraction at commensurate
pressures reveal a tilting of the Cu spins out of the plane
with a critical exponent characteristic of 3D transitions.
The addition of anisotropic, interplane, spin-orbit terms in
the venerable Shastry-Sutherland Hamiltonian accounts for
the influence of the third dimension.},
Doi = {10.1073/pnas.1413318111},
Key = {fds302511}
}
@article{fds343599,
Author = {Shi, Z and Steinhardt, W and Graf, D and Corboz, P and Weickert, F and Harrison, N and Jaime, M and Marjerrison, C and Dabkowska, HA and Mila,
F and Haravifard, S},
Title = {Emergent bound states and impurity pairs in chemically doped
Shastry-Sutherland system},
Journal = {NATURE COMMUNICATIONS},
Volume = {10},
Number = {1},
Pages = {9 pages},
Publisher = {NATURE PUBLISHING GROUP},
Year = {2019},
Month = {June},
url = {http://dx.doi.org/10.1038/s41467-019-10410-x},
Abstract = {Impurities often play a defining role in the ground states
of frustrated quantum magnets. Studies of their effects are
crucial in understanding of the phase diagram in these
materials. SrCu2(BO3)2, an experimental realization of the
Shastry-Sutherland (SS) lattice, provides a unique model
system for such studies using both experimental and
numerical approaches. Here we report effects of impurities
on the crystals of bound states, and doping-induced emergent
ground states in Mg-doped SrCu2(BO3)2, which remain stable
in high magnetic fields. Using four complementary
magnetometry techniques and theoretical simulations, a rich
impurity-induced phenomenology at high fields is discovered.
The results demonstrate a rare example in which even a small
doping concentration interacts strongly with both triplets
and bound states of triplets, and thus plays a significant
role in the magnetization process even at high magnetic
fields. Our findings provide insights into the study of
impurity effects in geometrically frustrated quantum
magnets.},
Doi = {10.1038/s41467-019-10410-x},
Key = {fds343599}
}
@article{fds302506,
Author = {Asano, T and Nishimura, T and Ichimura, S and Inagaki, Y and Kawae, T and Fukui, T and Narumi, Y and Kindo, K and Ito, T and Haravifard, S and Gaulin, BD},
Title = {Erratum: Magnetic ordering and tunable structural phase
transition in the chromic compound CuMoO4
(Journal of the Physical Society of Japan (2011) 80
093708))},
Journal = {Journal of the Physical Society of Japan},
Volume = {80},
Number = {11},
Pages = {118001-118001},
Publisher = {Physical Society of Japan},
Year = {2011},
Month = {November},
ISSN = {0031-9015},
url = {http://dx.doi.org/10.1143/JPSJ.80.118001},
Doi = {10.1143/JPSJ.80.118001},
Key = {fds302506}
}
@article{fds348017,
Author = {Steinhardt, W.M. and Shi, Z. and Samarakoon, A. and Dissanayake, S. and Graf, D. and Liu, Y. and Zhu, W. and Marjerrison, C. and Batista, C.D. and Haravifard, S},
Title = {Field-Induced Phase Transition of the Spin Liquid State in
Triangular Antiferromagnet YbMgGaO4},
Journal = {With Reviewers at Nature Communications, arXiv:1902.07825
[cond-mat.str-el]},
Year = {2019},
Month = {February},
Abstract = {The triangular antiferromagnet YbMgGaO4 has emerged as a
candidate for hosting quantum spin liquid state, an exotic
state of matter featuring a high degree of entanglement and
often characterized as without magnetic ordering in the
zero-temperature limit. However, the nature of the ground
state in this system has been the subject of ardent debates,
as recent work has shown that chemical disorder may
contribute to quantum spin liquid-like features. Here we
report a field-induced phase transition observed via diffuse
neutron scattering and magnetic susceptibility measurements.
Comparisons to Monte Carlo simulations, using semi-classical
spins and disorder, and Density Matrix Renormalization Group
for the zero-temperature limit, reveal crucial information
about the ground state and the roles that thermal
fluctuations and chemical disorder play in the observed
behavior.},
Key = {fds348017}
}
@article{fds375118,
Author = {Dissanayake, SE and Matsuda, M and Yoshimi, K and Kasamatsu, S and Ye,
F and Chi, S and Steinhardt, W and Fabbris, G and Haravifard, S and Cheng,
J and Yan, J and Gouchi, J and Uwatoko, Y},
Title = {Helical magnetic state in the vicinity of the
pressure-induced superconducting phase in
MnP},
Journal = {Physical Review Research},
Volume = {5},
Number = {4},
Pages = {p.043026},
Year = {2023},
Month = {October},
url = {http://dx.doi.org/10.1103/PhysRevResearch.5.043026},
Abstract = {MnP is a metal that shows successive magnetic transitions
from paramagnetic to ferromagnetic and helical magnetic
phases at ambient pressure with decreasing temperature. With
applied pressure, the magnetic transition temperatures
decrease and superconductivity appears around 8 GPa where
the magnetic order is fully suppressed and the quantum
critical behavior is observed. These results suggest that
MnP is an unconventional superconductor in which magnetic
fluctuations may be relevant to the superconducting pairing
mechanism. In order to elucidate the magnetic ground state
adjacent to the superconducting phase first discovered in
Mn-based materials, high-pressure neutron diffraction
measurements have been performed in hydrostatic pressure up
to 7.5 GPa. The helical magnetic structure with the
propagation vector along the b axis, reported previously at
3.8 GPa, was found to be robust up to 7.5 GPa.
First-principles and classical Monte Carlo calculations have
also been performed to understand how the pressure-driven
magnetic phase transitions are coupled with change of the
exchange interactions. The calculations, which qualitatively
reproduce the magnetic structures as a function of pressure,
suggest that the exchange interactions change drastically
with applied pressure and the further-neighbor interactions
become more influential at high pressures. Combining the
experimental and theoretical results, we describe the detail
of exchange interactions in the vicinity of the
superconducting phase, which is critical to understand the
pairing mechanism of the unconventional superconductivity in
MnP.},
Doi = {10.1103/PhysRevResearch.5.043026},
Key = {fds375118}
}
@article{fds302502,
Author = {Gaulin, BD and Lee, SH and Haravifard, S and Castellan, JP and Berlinsky, AJ and Dabkowska, HA and Qiu, Y and Copley,
JRD},
Title = {High-resolution study of spin excitations in the singlet
ground state of SrCu2(BO3)2.},
Journal = {Physical review letters},
Volume = {93},
Number = {26 Pt 1},
Pages = {267202},
Year = {2004},
Month = {December},
ISSN = {0031-9007},
url = {http://dx.doi.org/10.1103/physrevlett.93.267202},
Abstract = {High-resolution, inelastic neutron scattering measurements
on SrCu2(BO3)2, a realization of the Shastry-Sutherland
model for two-dimensional Heisenberg antiferromagnets,
reveal the dispersion of the three single triplet
excitations continuously across the (H,0) direction within
its tetragonal basal plane. These measurements also show
distinct Q dependencies for the single and multiple triplet
excitations, and that these excitations are largely
dispersionless perpendicular to this plane. The temperature
dependence of the intensities of these excitations is well
described as the complement of the dc susceptibility of
SrCu2(BO3)2.},
Doi = {10.1103/physrevlett.93.267202},
Key = {fds302502}
}
@article{fds302503,
Author = {Haravifard, S and Dunsiger, SR and El Shawish and S and Gaulin, BD and Dabkowska, HA and Telling, MTF and Perring, TG and Bonca,
J},
Title = {In-gap spin excitations and finite triplet lifetimes in the
dilute singlet ground state system SrCu(2-x)Mgx(BO3)2.},
Journal = {Physical review letters},
Volume = {97},
Number = {24},
Pages = {247206},
Year = {2006},
Month = {December},
ISSN = {0031-9007},
url = {http://dx.doi.org/10.1103/physrevlett.97.247206},
Abstract = {High resolution neutron scattering measurements on a single
crystal of SrCu(2-x)Mgx(BO3)2 with x approximately 0.05
reveal the presence of new spin excitations within the gap
of this quasi-two-dimensional, singlet ground state system.
The application of a magnetic field induces Zeeman-split
states associated with S=1/2 unpaired spins which are
antiferromagnetically correlated with the bulk singlet.
Substantial broadening of both the one- and two-triplet
excitations in the doped single crystal is observed, as
compared with pure SrCu2(BO3)2. Theoretical calculations
using a variational algorithm and a single quenched magnetic
vacancy on an infinite lattice are shown to qualitatively
account for these effects.},
Doi = {10.1103/physrevlett.97.247206},
Key = {fds302503}
}
@article{fds359471,
Author = {S. Haravifard and Shi, Z and Kuhn, SJ and Flicker, F and Helm, T and Lee, J and Steinhardt,
W and Dissanayake, S and Graf, D and Ruff, J and Fabbris, G and Haskel, D and Haravifard, S},
Title = {Incommensurate two-dimensional checkerboard charge density
wave in the low-dimensional superconductor
Ta4Pd3Te16},
Journal = {Physical Review Research},
Volume = {2},
Number = {4},
Year = {2020},
Month = {December},
url = {http://dx.doi.org/10.1103/PhysRevResearch.2.042042},
Abstract = {We report the observation of a two-dimensional (2D)
checkerboard charge density wave (CDW) in the
low-dimensional superconductor Ta4Pd3Te16. By determining
its CDW properties across the temperature-pressure (T-P)
phase diagram and comparing with prototypical CDW materials,
we conclude that Ta4Pd3Te16 features (a) an incommensurate
CDW with a mixed character of dimensions [quasi-1D (Q1D)
considering its needlelike shape along the b axis, Q2D as
the CDW has checkerboard wave vectors, and 3D because of CDW
projections along all three axes], and (b) one of the
weakest CDWs compared to its superconductivity (SC), i.e.,
enhanced SC with respect to CDW, suggesting an interesting
interplay of the two orders.},
Doi = {10.1103/PhysRevResearch.2.042042},
Key = {fds359471}
}
@article{fds302507,
Author = {Asano, T and Nishimura, T and Ichimura, S and Inagaki, Y and Kawae, T and Fukui, T and Narumi, Y and Kindo, K and Ito, T and Haravifard, S and Gaulin, BD},
Title = {Magnetic ordering and tunable structural phase transition in
the chromic compound CuMoO4},
Journal = {Journal of the Physical Society of Japan},
Volume = {80},
Number = {9},
Pages = {093708-093708},
Publisher = {Physical Society of Japan},
Year = {2011},
Month = {September},
ISSN = {0031-9015},
url = {http://dx.doi.org/10.1143/JPSJ.80.093708},
Abstract = {We report the first observation of long-range magnetic order
in the chromic compound CuMoO4 at 1.75 K by means of a
specific heat measurement in zero magnetic field.
Magnetization measurements performed up to 57 T at 4.2 K
indicate a plateau at 1/3 of the saturated magnetization
consistent with a simple magnetic model of two
non-interacting Cu2+ spins and two isolated
antiferromagnetic dimers (J=kB = 26 K). A large
temperature-hysteresis in the magnetic susceptibility is
observed to originate from the structural phase transition
and to be closely related to chromism between α-CuMoO4
(green) and γ-CuMoO4 (brownish-red). This discontinuous
phase transition is tunable using substitutional effects in
Cu1-xZnxMoO4 (0 ≥ × ≤ 0.1) and CuMo1-yWyO4 (0 ≤y
≤0.1) over a wide range of temperatures. © 2011 The
Physical Society of Japan.},
Doi = {10.1143/JPSJ.80.093708},
Key = {fds302507}
}
@article{fds302504,
Author = {Haravifard, S and Rule, KC and Dabkowska, HA and Gaulin, BD and Yamani,
Z and Buyers, WJL},
Title = {Neutron and x-ray scattering studies of the lightly doped
spin-Peierls system Cu1-xCdxGeO3},
Journal = {Journal of Physics Condensed Matter},
Volume = {19},
Number = {43},
Pages = {436222-436222},
Publisher = {IOP Publishing},
Year = {2007},
Month = {October},
ISSN = {0953-8984},
url = {http://dx.doi.org/10.1088/0953-8984/19/43/436222},
Abstract = {Single crystals of the lightly doped spin-Peierls system Cu
1-xCdxGeO3 have been studied using bulk susceptibility,
x-ray diffraction, and inelastic neutron scattering
techniques. We investigate the triplet gap in the magnetic
excitation spectrum of this quasi-one-dimensional quantum
antiferromagnet, and its relation to the spin-Peierls
dimerization order parameter. We employ two different
theoretical forms to model the inelastic neutron scattering
cross section and χ′′(Q,ω), and show the sensitivity
of the gap energy to the choice of ). We find that a finite
gap exists at the spin-Peierls phase transition. © IOP
Publishing Ltd.},
Doi = {10.1088/0953-8984/19/43/436222},
Key = {fds302504}
}
@article{fds302510,
Author = {Haravifard, S and Gaulin, BD and Yamani, Z and Dunsiger, SR and Dabkowska, HA},
Title = {Neutron scattering from the static and dynamic lattice of
SrCu 2(BO 3) 2 in its
Shastry-Sutherland singlet ground state},
Journal = {Physical Review B - Condensed Matter and Materials
Physics},
Volume = {85},
Number = {13},
Publisher = {American Physical Society (APS)},
Year = {2012},
Month = {April},
ISSN = {1098-0121},
url = {http://dx.doi.org/10.1103/PhysRevB.85.134104},
Abstract = {Elastic and inelastic neutron scattering results show that
SrCu 2(BO 3) 2 enters its low-temperature singlet ground
state below 10 K without an obvious accompanying structural
phase transition, despite suggestions emanating from earlier
heat capacity measurements. However, evidence for
significant spin-phonon coupling is found in the energy
widths, and the corresponding lifetimes, of transverse
acoustic phonons propagating in the (H00) direction of the
Shastry-Sutherland, tetragonal basal plane. Transverse
acoustic phonons with energies comparable to and higher than
the onset of the two-triplet continuum show substantially
increased lifetimes on entering the singlet ground state
below ∼10 K. This is qualitatively consistent with the
removal of a decay channel for the phonons due to the
gapping of the spin excitation spectrum in SrCu 2(BO 3) 2 at
low temperatures. © 2012 American Physical
Society.},
Doi = {10.1103/PhysRevB.85.134104},
Key = {fds302510}
}
@article{fds302509,
Author = {Feng, Y and Wang, J and Jaramillo, R and van Wezel, J and Haravifard, S and Srajer, G and Liu, Y and Xu, Z-A and Littlewood, PB and Rosenbaum,
TF},
Title = {Order parameter fluctuations at a buried quantum critical
point.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {109},
Number = {19},
Pages = {7224-7229},
Year = {2012},
Month = {May},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.1202434109},
Abstract = {Quantum criticality is a central concept in condensed matter
physics, but the direct observation of quantum critical
fluctuations has remained elusive. Here we present an X-ray
diffraction study of the charge density wave (CDW) in
2H-NbSe(2) at high pressure and low temperature, where we
observe a broad regime of order parameter fluctuations that
are controlled by proximity to a quantum critical point.
X-rays can track the CDW despite the fact that the quantum
critical regime is shrouded inside a superconducting phase;
and in contrast to transport probes, allow direct
measurement of the critical fluctuations of the charge
order. Concurrent measurements of the crystal lattice point
to a critical transition that is continuous in nature. Our
results confirm the long-standing expectations of enhanced
quantum fluctuations in low-dimensional systems, and may
help to constrain theories of the quantum critical Fermi
surface.},
Doi = {10.1073/pnas.1202434109},
Key = {fds302509}
}
@article{fds361658,
Author = {Shi, Z and Dissanayake, S and Corboz, P and Steinhardt, W and Graf, D and Silevitch, DM and Dabkowska, HA and Rosenbaum, TF and Mila, F and Haravifard, S},
Title = {Phase diagram of the Shastry-Sutherland Compound SrCu2(BO3)2
under extreme combined conditions of field and
pressure},
Year = {2021},
Month = {July},
Abstract = {Motivated by the intriguing properties of the
Shastry-Sutherland compound SrCu2(BO3)2 under pressure, with
a still debated intermediate plaquette phase appearing at
around 20 kbar and a possible deconfined critical point at
higher pressure upon entering the antiferromagnetic phase,
we have investigated its high-field properties in this
pressure range using tunnel diode oscillator (TDO)
measurements. The two main new phases revealed by these
measurements are fully consistent with those identified by
infinite Projected Entangled Pair states (iPEPS)
calculations of the Shastry-Sutherland model, a 1/5 plateau
and a 10 x 2 supersolid. Remarkably, these phases are
descendants of the full-plaquette phase, the prominent
candidate for the intermediate phase of SrCu2(BO3)2. The
emerging picture for SrCu2(BO3)2 is shown to be that of a
system dominated by a tendency to an orthorhombic distortion
at intermediate pressure, an important constraint on any
realistic description of the transition into the
antiferromagnetic phase.},
Key = {fds361658}
}
@article{fds359158,
Author = {Steinhardt, W and Maksimov, PA and Dissanayake, S and Shi, Z and Butch,
NP and Graf, D and Podlesnyak, A and Liu, Y and Zhao, Y and Xu, G and Lynn,
JW and Marjerrison, C and Chernyshev, AL and Haravifard,
S},
Title = {Phase diagram of YbZnGaO4 in applied magnetic
field},
Journal = {npj Quantum Materials},
Volume = {6},
Number = {1},
Publisher = {Springer Science and Business Media LLC},
Year = {2021},
Month = {December},
url = {http://dx.doi.org/10.1038/s41535-021-00380-z},
Abstract = {Recently, Yb-based triangular-lattice antiferromagnets have
garnered significant interest as possible quantum
spin-liquid candidates. One example is YbMgGaO4, which
showed many promising spin-liquid features, but also
possesses a high degree of disorder owing to site-mixing
between the non-magnetic cations. To further elucidate the
role of chemical disorder and to explore the phase diagram
of these materials in applied field, we present neutron
scattering and sensitive magnetometry measurements of the
closely related compound, YbZnGaO4. Our results suggest a
difference in magnetic anisotropy between the two compounds,
and we use key observations of the magnetic phase crossover
to motivate an exploration of the field- and exchange
parameter-dependent phase diagram, providing an expanded
view of the available magnetic states in applied field. This
enriched map of the phase space serves as a basis to
restrict the values of parameters describing the magnetic
Hamiltonian with broad application to recently discovered
related materials.},
Doi = {10.1038/s41535-021-00380-z},
Key = {fds359158}
}
@article{fds369773,
Author = {Haravifard, S},
Title = {Pressure and field: the keys to unlock exotic states in
quantum materials},
Journal = {Acta Crystallographica Section A Foundations and
Advances},
Volume = {78},
Number = {a1},
Pages = {a208-a208},
Publisher = {International Union of Crystallography (IUCr)},
Year = {2022},
Month = {July},
url = {http://dx.doi.org/10.1107/s2053273322097911},
Doi = {10.1107/s2053273322097911},
Key = {fds369773}
}
@book{fds322486,
Author = {Haravifard, S and Yamani, Z and Gaulin, BD},
Title = {Quantum Phase Transitions},
Volume = {48},
Pages = {43-144},
Booktitle = {Experimental Methods in the Physical Sciences},
Publisher = {Elsevier},
Year = {2015},
Month = {January},
ISBN = {9780128020494},
url = {http://dx.doi.org/10.1016/B978-0-12-802049-4.00002-6},
Abstract = {Quantum phase transition (QPT) occurs at zero temperature
where thermal fluctuations are absent and instead the
transition is driven by quantum fluctuations which are tuned
by variations in some nonthermal parameters, such as
pressure, magnetic field, or chemical composition, as
demanded by Heisenberg's uncertainty principle. Although QPT
occurs at zero temperature, its influence expands to a broad
nonzero temperature regime of quantum criticality, enabling
us to study these phenomena through variety of experimental
techniques. This chapter considers QPTs in quantum magnets,
presenting a brief introduction to several well-studied
systems and reviewing experimental examples for spin dimers,
geometrically frustrated magnets, heavy fermions, itinerant
magnets, and transverse field Ising systems, with focus on
neutron scattering techniques utilized to deliver a more
comprehensive picture of the fundamental physics behind the
QPT in these systems.},
Doi = {10.1016/B978-0-12-802049-4.00002-6},
Key = {fds322486}
}
@article{fds360572,
Author = {Bag, R and Ennis, M and Liu, C and Dissanayake, SE and Shi, Z and Liu, J and Balents, L and Haravifard, S},
Title = {Realization of quantum dipoles in triangular lattice crystal
Ba3Yb(B O3)3},
Journal = {Physical Review B},
Volume = {104},
Number = {22},
Pages = {L220403},
Year = {2021},
Month = {December},
url = {http://dx.doi.org/10.1103/PhysRevB.104.L220403},
Abstract = {We investigate the thermodynamic properties of the
ytterbium-based triangular lattice compound Ba3Yb(BO3)3. The
results demonstrate the absence of any long-range ordering
down to 56 mK. Analysis of the magnetization,
susceptibility, and specific heat measurements suggests that
Ba3Yb(BO3)3 may realize an S=12 quantum dipole lattice, in
which the dominant interaction is the long-range
dipole-dipole coupling on the geometrically frustrated
triangular lattice, and exchange interactions are
subdominant or negligible.},
Doi = {10.1103/PhysRevB.104.L220403},
Key = {fds360572}
}
@article{fds375137,
Author = {Ennis, M and Bag, R and Liu, C and Dissanayake, SE and Kolesnikov, AI and Balents, L and Haravifard, S},
Title = {Realization of two-sublattice exchange physics in the
triangular lattice compound Ba3Er(BO3)3},
Year = {2023},
Month = {June},
Key = {fds375137}
}
@article{fds375337,
Author = {Ennis, M and Bag, R and Liu, C and Dissanayake, SE and Kolesnikov, AI and Balents, L and Haravifard, S},
Title = {Realization of two-sublattice exchange physics in the
triangular lattice compound Ba3Er(BO3)3},
Journal = {Communications Physics},
Volume = {7},
Number = {1},
Publisher = {Springer Science and Business Media LLC},
Year = {2024},
Month = {December},
url = {http://dx.doi.org/10.1038/s42005-024-01532-w},
Abstract = {Geometric frustration commonly occurs in materials where
magnetic rare-earth ions are arranged on a two-dimensional
triangular lattice. These compounds have been gaining
significant attention lately, as they hold the promise of
revealing unique quantum states of matter. However, little
attention has been devoted to cases where spin- 12
rare-earth ions are substituted with ions exhibiting higher
spin multiplicities. Here, we successfully synthesize
high-quality single crystal samples of Ba3Er(BO3)3, which is
part of the family of triangular lattice compounds. In our
experiments, conducted at extremely low temperatures (around
100 millikelvin), we observe two sublattice exchange
interactions in Ba3Er(BO3)3, resulting in the hexagonal
lattice spins exhibiting a mixture of ferromagnetic and
antiferromagnetic tendencies. Our theoretical analysis
suggest that this behavior may be attributed to the distinct
positions of magnetic ions within the crystal lattice.
However, the presence of quantum effects adds an extra layer
of complexity to our findings, calling for further
exploration.},
Doi = {10.1038/s42005-024-01532-w},
Key = {fds375337}
}
@article{fds375109,
Author = {Ennis, M. and Bag, R. and Liu, C. and Dissanayake, S.E. and Kolesnikov, A.I. and Balents, L. and Haravifard, S.},
Title = {Realization of Two-Sublattice Exchange Physics in Triangular
Antiferromagnet Ba3Er(BO3)3},
Journal = {Nature Communications Physics},
Year = {2023},
Key = {fds375109}
}
@article{fds375120,
Author = {Xu, S and Bag, R and Sherman, NE and Yadav, L and Kolesnikov, AI and Podlesnyak, AA and Moore, JE and Haravifard, S},
Title = {Realization of U(1) Dirac Quantum Spin Liquid in
YbZn2GaO5},
Year = {2023},
Month = {May},
Key = {fds375120}
}
@article{fds302513,
Author = {Haravifard, S and Banerjee, A and van Wezel, J and Silevitch, DM and dos
Santos, AM and Lang, JC and Kermarrec, E and Srajer, G and Gaulin, BD and Molaison, JJ and Dabkowska, HA and Rosenbaum, TF},
Title = {Reply to Zayed: Interplay of magnetism and structure in the
Shastry-Sutherland model.},
Journal = {Proceedings of the National Academy of Sciences of the
United States of America},
Volume = {112},
Number = {5},
Pages = {E383-E384},
Year = {2015},
Month = {February},
ISSN = {0027-8424},
url = {http://dx.doi.org/10.1073/pnas.1423100112},
Doi = {10.1073/pnas.1423100112},
Key = {fds302513}
}
@article{fds374152,
Author = {Pratt, FL and Lang, F and Steinhardt, W and Haravifard, S and Blundell,
SJ},
Title = {Spin dynamics, entanglement, and the nature of the spin
liquid state in YbZnGaO4},
Journal = {Physical Review B},
Volume = {106},
Number = {6},
Pages = {L060401},
Year = {2022},
Month = {August},
url = {http://dx.doi.org/10.1103/PhysRevB.106.L060401},
Abstract = {Electron spin dynamics was studied down to 80 mK in the
triangular-lattice quantum spin-liquid candidate YbZnGaO4
using muon spin relaxation, finding no evidence for freezing
or ordering of the Yb spins. The muon spin relaxation rate
can be represented by the sum of two contributions, one
dependent on longitudinal magnetic field and the other
independent of field. The field-dependent term follows the
form expected for two-dimensional diffusion of mobile spin
excitations. The spin-diffusion rate obtained for these
excitations in the high temperature paramagnetic regime is
comparable with the exchange coupling frequency J/h,
reducing significantly in the low temperature quantum
regime. This slowdown is assigned to the effect of quantum
entanglement. The exchange coupling J is estimated to be
2.0(2) K from the crossover between the two regimes. The
field-independent term is only weakly dependent on
temperature, and at 15 K its absolute value is consistent
with dipolar coupling of the muon to the three Yb moments
closest to the muon site, where the spin dynamics of these
moments is determined by exchange fluctuations. The
temperature-dependent properties in the quantum regime are
compared against the three possible U(1) spin-liquid models
that have been obtained for the strongly spin-orbit coupled
triangular lattice by Y.-D. Li, Y.-M. Lu, and G. Chen [Phys.
Rev. B 96, 054445 (2017)2469-995010.1103/PhysRevB.96.054445].
The comparison with theory takes published specific heat and
thermal conductivity data into account, along with the
spin-diffusion rate obtained from the muons. It is found
that the nodal spin-liquid model U1A11 containing both
linear and quadratic nodes provides better agreement with
experiment than either the U1A00 spinon Fermi surface (FS)
model or the U1A01 model that contains only linear
nodes.},
Doi = {10.1103/PhysRevB.106.L060401},
Key = {fds374152}
}
@article{fds375122,
Author = {Pratt, FL and Lang, F and Blundell, SJ and Steinhardt, W and Haravifard,
S and Mañas-Valero, S and Coronado, E and Huddart, BM and Lancaster,
T},
Title = {Studying spin diffusion and quantum entanglement with LF-
μsR},
Journal = {Journal of Physics: Conference Series},
Volume = {2462},
Number = {1},
Year = {2023},
Month = {January},
url = {http://dx.doi.org/10.1088/1742-6596/2462/1/012038},
Abstract = {LF-μSR studies have previously been used to study the
diffusive 1D motion of solitons and polarons in conducting
polymers. This type of study was also applied to
investigating the diffusive motion of spinons in spin-1/2
antiferromagnetic chains. Recently the method has been
extended to examples of 2D layered triangular spin lattices
which can support quantum spin liquid states, such as
1T-TaS2 and YbZnGaO4. These systems are found to show spin
dynamics that matches well to 2D spin diffusion, such a
model being found to provide a much better fit to the data
than previously proposed models for spin correlations in
such systems. In YbZnGaO4 the diffusion rate shows a clear
crossover between classical and quantum regimes as T falls
below the exchange coupling J. That the spin diffusion
approach works well in the high T classical region might be
expected, but it is found that it also works equally well in
the low T quantum region where quantum entanglement controls
the spin dynamics. Measurement of the diffusion rate allows
a T dependent length scale to be derived from the data that
can be assigned to a quantum entanglement length ζ E.
Another entanglement measure, the Quantum Fisher Information
F Q can also be obtained from the data and its T dependence
is compared to that of ζ E.},
Doi = {10.1088/1742-6596/2462/1/012038},
Key = {fds375122}
}
@article{fds361719,
Author = {Dissanayake, S and Shi, Z and Rau, JG and Bag, R and Steinhardt, W and Butch, NP and Frontzek, M and Podlesnyak, A and Graf, D and Marjerrison,
C and Liu, J and Gingras, MJP and Haravifard, S},
Title = {Towards understanding the magnetic properties of the
breathing pyrochlore compound Ba3Yb2Zn5O11: A single crystal
study},
Journal = {npj Quantum Materials},
Volume = {7},
Pages = {77},
Year = {2021},
Month = {November},
Abstract = {Ba3Yb2Zn5O11 is unique among breathing pyrochlore compounds
for being in the nearly decoupled limit where
inter-tetrahedron interactions are weak, hosting isolated
clusters or "molecular magnet" like tetrahedra of magnetic
ytterbium (Yb3+) ions. In this work, we present the first
study carried out on single-crystal samples of the breathing
pyrochlore Ba3Yb2Zn5O11, using a variety of magnetometry and
neutron scattering techniques along with theoretical
modeling. We employ inelastic neutron scattering to
investigate the magnetic dynamics as a function of applied
field (with respect to both magnitude and direction) down to
a temperature of 70 mK, where inelastic scattering reveals
dispersionless bands of excitations as found in earlier
powder sample studies, in good agreement with a
single-tetrahedron model. However, diffuse neutron
scattering at zero field and dc-susceptibility at finite
field exhibit features suggesting the presence of
excitations at low-energy that are not captured by the
single tetrahedron model. Analysis of the local structure
down to 2 K via pair distribution function analysis finds no
evidence of structural disorder. We conclude that effects
beyond the single tetrahedron model are important in
describing the low-energy, low temperature physics of
Ba3Yb2Zn5O11, but their nature remains undetermined.},
Key = {fds361719}
}
@article{fds374150,
Author = {Dissanayake, S and Shi, Z and Rau, JG and Bag, R and Steinhardt, W and Butch, NP and Frontzek, M and Podlesnyak, A and Graf, D and Marjerrison,
C and Liu, J and Gingras, MJP and Haravifard, S},
Title = {Towards understanding the magnetic properties of the
breathing pyrochlore compound Ba3Yb2Zn5O11through
single-crystal studies},
Journal = {npj Quantum Materials},
Volume = {7},
Number = {1},
Publisher = {Nature},
Year = {2022},
Month = {December},
url = {http://dx.doi.org/10.1038/s41535-022-00488-w},
Abstract = {Ba3Yb2Zn5O11 is exceptional among breathing pyrochlore
compounds for being in the nearly-decoupled limit where
inter-tetrahedron interactions are weak, hosting isolated
clusters or molecular magnet-like tetrahedra of magnetic
ytterbium (Yb3+) ions. In this work, we present the study
carried out on single-crystal samples of the breathing
pyrochlore Ba3Yb2Zn5O11, using a variety of magnetometry and
neutron scattering techniques along with theoretical
modeling. We employ inelastic neutron scattering to
investigate the magnetic dynamics as a function of applied
field (with respect to both magnitude and direction) down to
a temperature of 70 mK, where inelastic scattering reveals
dispersionless bands of excitations as found in earlier
powder sample studies, in good agreement with a
single-tetrahedron model. However, diffuse neutron
scattering at zero field and dc-susceptibility at finite
field exhibit features suggesting the presence of
excitations at low-energy that are not captured by the
single tetrahedron model. Analysis of the local structure
down to 2 K via pair distribution function analysis finds no
evidence of structural disorder. We conclude that effects
beyond the single tetrahedron model are important in
describing the low-energy, low-temperature physics of
Ba3Yb2Zn5O11, but their nature remains undetermined.},
Doi = {10.1038/s41535-022-00488-w},
Key = {fds374150}
}
@article{fds369774,
Author = {Haravifard, S},
Title = {Understanding quantum materials under extreme sample
environments},
Journal = {Acta Crystallographica Section A Foundations and
Advances},
Volume = {77},
Number = {a1},
Pages = {a149-a149},
Publisher = {International Union of Crystallography (IUCr)},
Year = {2021},
Month = {July},
url = {http://dx.doi.org/10.1107/s0108767321098500},
Doi = {10.1107/s0108767321098500},
Key = {fds369774}
}