Latest in cond-mat.str-el

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Neutron scattering study of commensurate magnetic ordering in single crystal CeSb$_2$Feb 21 2019Temperature and field-dependent magnetization $M(H,T)$ measurements and neutron scattering study of a single crystal CeSb$_2$ are presented. Several anomalies in the magnetization curves have been confirmed at low magnetic field, i.e., 15.6 K, 12 K, and ... More
Asymmetric Ferromagnetic Criticality in Pyrochlore Ferromagnet Lu$_2$V$_2$O$_7$Feb 21 2019Critical phenomenon at the phase transition reveals the universal and long-distance properties of the criticality. We study the ferromagnetic criticality of the pyrochlore magnet Lu$_2$V$_2$O$_7$ at the ferromagnetic transition ${T_\text{c}\approx 70\, ... More
Photoinduced Floquet topological magnons in Kitaev magnetsFeb 20 2019We study periodically driven pure Kitaev model and ferromagnetic phase of the Kitaev-Heisenberg model on the honeycomb lattice by off-resonant linearly and circularly-polarized lights at zero magnetic field. Using a combination of linear spin wave and ... More
Symmetry projected Jastrow mean field wavefunction in variational Monte CarloFeb 20 2019We extend our low-scaling variational Monte Carlo algorithm (VMC) algorithm [J. Chem. Theory Comput., 2018, 14, 6276] to optimize the symmetry projected Jastrow mean field (SJMF) wavefunctions. These wavefunctions consist of a symmetry-projected product ... More
Terahertz conductivity of the magnetic Weyl semimetal Mn$_{3}$Sn filmsFeb 20 2019Mn$_{3}$Sn is a non-collinear antiferromagnet which displays a large anomalous Hall effect at room temperature. It is believed that the principal contribution to its anomalous Hall conductivity comes from Berry curvature. Moreover, dc transport and photoemission ... More
Transferring the quantum state of electrons across a Fermi sea with Coulomb interactionFeb 20 2019The Coulomb interaction generally limits the quantum propagation of electrons. However, it can also provide a mechanism to transfer their quantum state over larger distances. Here, we demonstrate such a form of teleportation, across a metallic island ... More
Magnetic field induced antiferromagnetic tricritical points in Ce$_2 $Sb and Ce$_2 $BiFeb 20 2019We present a detailed investigation of the physical properties of Ce$_2 $Sb and Ce$_2 $Bi single crystals, which undergo antiferromagnetic transitions at around 8.2 and 10 K respectively. When magnetic fields are applied parallel to the $c$ axis, metamagnetic ... More
Magnetic proximity effect in [Nb/Gd] superlattices seen by neutron scatteringFeb 20 2019We have used spin-polarized neutron reflectometry to investigate the magnetization profile of superlattices composed of ferromagnetic Gd and superconducting Nb layers. We have observed a partial suppression of ferromagnetic (F) order of Gd layers in [Gd($d_F$)/Nb(25nm)]$_{12}$ ... More
Thermodynamic Quantum Time CrystalsFeb 20 2019Investigation of states with a periodic time dependence of physical quantities attracts a considerable interest now. Although it has been proposed initially that such states (coined Quantum Time Crystals) might be macroscopic and thermodynamically stable, ... More
Electron states and magnetic phase diagrams of strongly correlated systemsFeb 20 2019Various auxiliary-particle approaches to treat electron correlations in many-electron models are analyzed. Applications to copper-oxide layered systems are discussed. The ground-state magnetic phase diagrams are considered within the Hubbard and $s$-$d$ ... More
Dynamics of Strongly Correlated Systems and Dynamical Renormalization GroupFeb 19 2019We discuss the dynamics of the central spin model with the equation of motion technique. We show that a Hierarchy of Horrelations decoupling can provide accurate results for the dynamics, in comparison with more standard decoupling methods. We also demonstrate ... More
Superexchange interactions between spin-orbit-coupled $j\!\approx\!1/2$ ions in oxides with face-sharing ligand octahedraFeb 19 2019Using ab initio wave-function-based calculations, we provide valuable insights with regard to the magnetic exchange in 5$d$ and 4$d$ oxides with face-sharing ligand octahedra, BaIrO$_3$ and BaRhO$_3$. Surprisingly strong antiferromagnetic Heisenberg interactions ... More
Role of defects in determining the magnetic ground state of ytterbium titanateFeb 19 2019Pyrochlore systems are ideally suited to the exploration of geometrical frustration in three dimensions, and their rich phenomenology encompasses topological order and fractional excitations. Classical spin ices provide the first context in which it is ... More
Direct imaging of orbitals in quantum materialsFeb 19 2019The spectacular physical properties of quantum materials based on transition metal, rare earth, and actinide elements continue to challenge our comprehension of solid state physics and chemistry. The electronic states of these materials are dominated ... More
Direct Determination of Band Gap Renormalization in Photo-Excited Monolayer MoS2Feb 19 2019A key feature of monolayer semiconductors, such as transition-metal dichalcogenides, is the poorly screened Coulomb potential, which leads to large exciton binding energy (Eb) and strong renormalization of the quasiparticle bandgap (Eg) by carriers. The ... More
Ultrafast Dynamics of Strongly Correlated Fermions -- Nonequilibrium Green Functions and Selfenergy ApproximationsFeb 19 2019This article presents an overview on recent progress in the theory of nonequilibrium Green functions (NEGF). NEGF, presently, are the only \textit{ab-initio} quantum approach that is able to study the dynamics of correlations for long times in two and ... More
Interplay of charge-transfer and Mott-Hubbard physics approached by an efficient combination of self-interaction correction and dynamical mean-field theoryFeb 19 2019Late transition-metal oxides with small charge-transfer energy $\Delta$ raise issues for state-of-the-art correlated electronic structure schemes such as the combination of density functional theory (DFT) with dynamical mean-field theory (DMFT). The accentuated ... More
Topology and localization of a periodically driven Kitaev modelFeb 19 2019Periodically driven quantum many-body systems support anomalous topological phases of matter, which cannot be realized by static systems. In many cases, these anomalous phases can be many-body localized, which implies that they are stable and do not heat ... More
Evaporative cooling and self-thermalization in an open system of interacting fermionsFeb 19 2019We study depletion dynamics of an open system of weakly interacting fermions with two-body random interactions. In this model fermions are escaping from the high-energy one-particle orbitals, that mimics the evaporation process used in laboratory experiments ... More
Phase stabilization by electronic entropy in plutoniumFeb 19 2019(Pu) has an unusually rich phase diagram that includes seven distinct solid state phases and an unusually large 25% collapse in volume from its delta phase to its low temperature alpha phase via a series of structural transitions. Despite considerable ... More
Interacting Majorana fermions in strained nodal superconductorsFeb 18 2019Landau levels (LL) have been predicted to emerge in systems with Dirac nodal points under applied non-uniform strain. We consider 2D, $d_{xy}$ singlet (2D-S) and 3D $p \pm i p$ equal-spin triplet (3D-T) superconductors (SCs). We demonstrate the spinful ... More
Orientation of ground-state orbital in CeCoIn$_5$ and CeRhIn$_5$Feb 18 2019We present core level non-resonant inelastic x-ray scattering (NIXS) data of the heavy fermion compounds CeCoIn$_5$ and CeRhIn$_5$ measured at the Ce $N_{4,5}$-edges. The higher than dipole transitions in NIXS allow determining the orientation of the ... More
Classification of massive Dirac models with generic non-Hermitian perturbationsFeb 18 2019We present a systematic investigation of $d$-dimensional massive Dirac models perturbed by three different types of non-Hermitian terms: (i) non-Hermitian terms that anti-commute with the Dirac Hamiltonian, (ii) non-Hermitian kinetic terms, and (iii) ... More
Computational Studies and Algorithmic Research of Strongly Correlated MaterialsFeb 18 2019This PhD thesis conducts a focused study of strongly correlated materials with localized electron orbitals. We have studied two real materials (LuNiO$_3$ and VO$_2$) and one model system, i.e., the Anderson impurity model. The thesis is divided into two ... More
Dual Boson approach with instantaneous interactionFeb 18 2019The Dual Boson approach to strongly correlated systems generally involves a dynamic (frequency-dependent) interaction in the auxiliary impurity model. In this work, we explore the consequences of forcing this interaction to be instantaneous (frequency-independent) ... More
Anomalous thermal Hall effect in the topological antiferromagnetic stateFeb 18 2019The anomalous Hall effect (AHE), a Hall signal occurring without an external magnetic field, is one of the most significant phenomena. However, understanding the AHE mechanism has been challenging and largely restricted to ferromagnetic metals. Here, ... More
Hidden valence transition in URu2Si2?Feb 18 2019The term "hidden order" refers to an as yet unidentified form of broken-symmetry order parameter that is presumed to exist in the strongly correlated electron system URu2Si2 on the basis of the reported similarity of the heat capacity at its phase transition ... More
Bosonization with background $U(1)$ gauge fieldFeb 18 2019Bosonization is one of the most significant frameworks to analyze fermionic systems. In this work, we propose a new bosonization of Dirac fermion coupled with $U(1)$ background gauge field consistent with gauge invariance, global chiral anomaly matching ... More
Pressure-induced spin-state ordering in Sr$_2$CoO$_3$FFeb 18 2019We study theoretically low-temperature phases of a recently-synthesized compound Sr$_2$CoO$_3$F under pressure. The analysis combining LDA+DMFT and strong-coupling effective model points to the existence of not only normal paramagnetic and antiferromagnetic ... More
Magnetisation plateaux of the quantum pyrochlore Heisenberg antiferromagnetFeb 18 2019We predict magnetisation plateaux ground states for $S=1/2$ Heisenberg antiferromagnets on pyrochlore lattices by formulating arguments based on gauge and spin-parity transformations. We derive a twist operator appropriate to the pyrochlore lattice, and ... More
Impact of off-diagonal exchange interactions on the Kitaev spin liquid state of $α$-RuCl$_3$Feb 18 2019Motivated by the recent experimental observation of the half-quantized thermal Hall conductivity for the candidate material of the Kitaev spin liquid, $\alpha$-RuCi$_3$[ Y. Kasahara {\it et al.}, Nature {\bf 559}, 227 (2018)], we investigate effects of ... More
Quantum magnetisms in uniform triangular lattices Li2AMo3O8 (A = In, Sc)Feb 18 2019Molecular based spin-1/2 triangular lattice systems such as LiZn$_2$Mo$_3$O$_8$ have attracted research interest. Distortions, defects, and intersite disorder are suppressed in such molecular-based magnets, and intrinsic geometrical frustration gives ... More
Evidence for gradual evolution of low-energy fluctuations underlying the first-order structural and valence order in YbPdFeb 18 2019The valence orders at $T_a=125$ K and $T_b=105$ K in the cubic compound YbPd have been investigated by $^{105}$Pd-nuclear magnetic resonance (NMR) measurements. Significant decrease in the density of states at the Fermi energy below $T_a$ is evident from ... More
Numerical Investigation of Spin Excitations in a Doped Spin ChainFeb 17 2019We study the doping evolution of spin excitations in a 1D Hubbard model and its downfolded spin Hamiltonians, by using exact diagonalization combined with cluster perturbation theory. In all models, we observe hardening (softening) of spin excitations ... More
Electrical writing, deleting, reading, and moving of magnetic skyrmioniums in a racetrack deviceFeb 17 2019A magnetic skyrmionium (also called 2$\pi$-skyrmion) can be understood as a skyrmion - a topologically non-trivial magnetic whirl - which is situated in the center of a second skyrmion with reversed magnetization. Here, we propose a new optoelectrical ... More
Vison Crystals in an Extended Kitaev Model on the Honeycomb LatticeFeb 16 2019We introduce an extension of the Kitaev honeycomb model by including four-spin interactions that preserve the local gauge structure and hence the integrability of the original model. The extended model has a rich phase diagram containing five distinct ... More
Phase transition in a noisy Kitaev toric code modelFeb 16 2019It is well-known that the partition function of a classical spin model can be mapped to a quantum entangled state where some properties on one side can be used to find new properties on the other side. However, the consequences of the existence of a classical ... More
1d lattice models for the boundary of 2d "Majorana" fermion SPTs: Kramers-Wannier duality as an exact $Z_2$ symmetryFeb 15 2019It is well known that symmetry protected topological (SPT) phases host non-trivial boundaries that cannot be mimicked in a lower-dimensional system with a conventional realization of symmetry. However, for SPT phases of bosons (fermions) within the cohomology ... More
High-Pressure Laser Floating Zone FurnaceFeb 15 2019The floating zone technique is a well-established single crystal growth method in materials research, able to produce volumetrically large specimens with extremely high purities. However, traditional furnace designs have relied on heating from high-powered ... More
Gutzwiller projection for exclusion of holes: Application to strongly correlated Ionic Hubbard Model and Binary AlloysFeb 15 2019We consider strongly correlated limit of variants of the Hubbard model (HM) in which on parts of the system it is energetically favourable to project out doublons from the low energy Hilbert space while on other sites of the system it is favourable to ... More
Is there a superconducting phase in the half-filled ionic Hubbard model ?Feb 15 2019We investigate the ionic Hubbard model (IHM) at half-filling in the limit of strong correlations and large ionic potential. The low energy effective Hamiltonian in this limit, obtained by a similarity transformation, is a modified $t-J$ model with effective ... More
Impurity-induced triple point fermions in twisted bilayer grapheneFeb 15 2019Triple point fermions are elusive electronic excitations that generalize Dirac and Weyl modes beyond the conventional high energy paradigm. Yet, finding real materials naturally hosting these excitations at the Fermi energy has remained challenging. Here ... More
Cubic B20 helimagnets with quenched disorder in magnetic fieldFeb 15 2019We theoretically address the problem of cubic B20 helimagnets with small concentration ${c \ll 1}$ of defect bonds in external magnetic field $\bf H$, which is relevant to mixed B20 compounds at small dopant concentrations. We assume that Dzyaloshinskii-Moriya ... More
Easy-plane QED$_3$'s in the large $N_f$ limitFeb 15 2019We consider Quantum Electrodynamics in $2{+}1$ dimensions with $N_f$ fermionic or bosonic flavors, allowing for interactions that respect the global symmetry $U(N_f/2)^2$. There are four bosonic and four fermionic fixed points, which we analyze using ... More
Magnetic states of Ni-Mn-Sn based shape memory alloy: a combined muon spin relaxation and neutron diffraction studyFeb 15 2019The fascinating multiple magnetic states observed in the Ni-Mn-Sn based metamagnetic shape memory alloy are addressed through a combined muon spin relaxation (muSR) and neutron powder diffraction studies. The material used in the present investigation ... More
Projected site-occupation embedding theory: a rigorous embedding combining wavefunction theory and density functional theoryFeb 15 2019Site-occupation embedding theory (SOET) [B. Senjean et al., Theo. Chem. Acc. (2018) 137:169] is an in-principle exact embedding method combining wavefunction theory and density functional theory that yields promising results when applied to the one-dimensional ... More
Microscopic Theory of $Γ_3$ Quadrupole Ordering in Pr Compounds on the Basis of a $j$-$j$ Coupling SchemeFeb 15 2019Toward the understanding of incommensurate $\Gamma_3$ quadrupole ordering in PrPb$_3$, we develop a microscopic theory of multipole ordering in $f^2$-electron systems from an itinerant picture on the basis of a $j$-$j$ coupling scheme. For this purpose, ... More
Electronic structure and 4f-electron character in Ce2PdIn8 studied by angle-resolved photoemission spectroscopyFeb 15 2019The localized-to-itinerant transition of f electrons lies at the heart of heavy-fermion physics, but has only been directly observed in single-layer Ce-based materials. Here, we report a comprehensive study on the electronic structure and nature of the ... More
Entanglement entropy and computational complexity of the Anderson impurity model out of equilibrium II: driven dynamicsFeb 15 2019We study the growth of entanglement entropy and bond dimension with time in density matrix renormalization group simulations of the periodically driven single-impurity Anderson model. The growth of entanglement entropy is found to be related to the ordering ... More
Direct determination of mode-projected electron-phonon coupling in the time-domainFeb 14 2019Ultrafast spectroscopies have become an important tool for elucidating the microscopic description and dynamical properties of quantum materials. In particular, by tracking the dynamics of non-thermal electrons, a material's dominant scattering processes ... More
Metallicity of oxygen-deficient EuTiO$_3$Feb 14 2019We report on a study of charge transport in EuTiO$_{3-\delta}$ single crystals with carrier density tuned across several orders of magnitude. Comparing this system with other quasi-cubic perovskites, in particular strontium titanate, we draw a comprehensive ... More
Sign changes of the Hall coefficient in Sr$_2$RuO$_4$ reveal coherent-to-incoherent and elastic-to-inelastic crossoversFeb 14 2019The Hall coefficient $R_H$ of Sr$_2$RuO$_4$ exhibits an unusual non-monotonic temperature dependence with two sign reversals. We show that this behavior is the signature of two crossovers which are key to the physics of this material. The initial rise ... More
Polarization resolved Cu $L_3$-edge resonant inelastic x-ray scattering of orbital and spin excitations in NdBa$_{2}$Cu$_{3}$O$_{7-δ}$Feb 14 2019High resolution resonant inelastic x-ray scattering (RIXS) has proven particularly effective in the determination of crystal field and spin excitations in cuprates. Its strength lies in the large Cu $L_{3}$ resonance and in the fact that the scattering ... More
Competing phases of interacting electrons on triangular lattices in moiré heterostructuresFeb 14 2019We study the quantum many-body instabilities of interacting electrons with SU(2)$\times$SU(2) symmetry in spin and orbital degrees of freedom on the triangular lattice near van-Hove filling. Our work is motivated by effective models for the flat bands ... More
Coupled dynamics of long-range and internal spin cluster order in Cu$_{2}$OSeO$_{3}$Feb 14 2019Cu$_4$ triplet clusters form the relevant spin entity for the formation of long-range magnetic order in the cluster magnet Cu$_2$OSeO$_3$. Using time-resolved Raman spectroscopy, we probed photoinduced spin and lattice dynamics in this Mott insulator. ... More
Intrinsic long range antiferromagnetic coupling in dilutely V doped CuInTe$_2$Feb 14 2019Despite the various magnetic orders mediated by superexchange mechanism, the existence of a long range antiferromagnetic (AFM) coupling is unknown. Based on DFT calculations, we discovered an intrinsic long range AFM coupling in V doped CuInTe$_2$. The ... More
Intrinsic long range antiferromagnetic coupling in dilutely V doped CuInTe$_2$Feb 14 2019Feb 15 2019Despite the various magnetic orders mediated by superexchange mechanism, the existence of a long range antiferromagnetic (AFM) coupling is unknown. Based on DFT calculations, we discovered an intrinsic long range AFM coupling in V doped CuInTe$_2$. The ... More
Quantized ΔS=2 Excitation Spectra by Confinement in an S=1 Spin ChainFeb 14 2019We calculate the dynamical spin-structure factor of the S=1 Ising spin chain with negative single-ion anisotropy in magnetic fields using the infinite time-evolving-block-decimation algorithm. We show that when the transverse magnetic field is applied, ... More
Isometric Tensor Network States in Two DimensionsFeb 13 2019Tensor network states (TNS) are a promising but numerically challenging tool for simulating two-dimensional (2D) quantum many-body problems. We introduce an isometric restriction of the TNS ansatz that allows for highly efficient contraction of the network. ... More
Incommensurate $2k_F$ density wave quantum criticality in two dimensional metalsFeb 13 2019We revisit the problem of two dimensional metals in the vicinity of a quantum phase transition to incommensurate $\mathbf{Q}=2k_F$ charge density wave order, where the order parameter wave vector $\mathbf{Q}$ connects two hot spots on the Fermi surface ... More
Detection of quantum phases via out-of-time-order correlatorsFeb 13 2019We elucidate the relation between out-of-time-order correlators (OTOCs) and the phase transitions via analytically studying the OTOC dynamics both in non-degenerate and degenerate spectra. Our method points to key ingredients to dynamically detect quantum ... More
Heating-Induced Long-Range $η$-Pairing in the Hubbard ModelFeb 13 2019We show how heating the spin degrees of freedom of the Hubbard model to infinite temperature can be used to melt the order within this sector and reach steady states, in any dimension, which have completely uniform long-range correlations between $\eta$ ... More
Anisotropic magnetic-field response of quantum critical fluctuations in Ni-doped CeCoIn5Feb 13 2019This paper demonstrates the anisotropic response of quantum critical fluctuations with respect to the direction of the magnetic field $B$ in Ni-doped CeCoIn$_5$ by measuring the magnetization $M$ and specific heat $C$. The results show that $M/B$ at $B=0.1\ ... More
Quantum Engineered Kondo LatticesFeb 13 2019Recent advances in atomic manipulation techniques have provided a novel bottom-up approach to investigating the unconventional properties and complex phases of strongly correlated electron materials. By engineering artificial condensed matter systems ... More
Holographic entanglement contour, bit threads, and the entanglement tsunamiFeb 12 2019We study the entanglement contour, a quasi-local measure of entanglement, and propose a generic formula for the contour in 1+1d quantum systems. We use this formalism to investigate the real space entanglement structure of various static CFTs as well ... More
Field-induced double dome and Bose-Einstein condensation in the crossing quantum spin chain system AgVOAsO4Feb 12 2019We present inelastic neutron scattering data on the quantum paramagnet AgVOAsO4 that establish the system is a S=1/2 alternating spin chain compound and provide a direct measurement of the spin gap. We also present experimental evidence for two different ... More
Scattering mechanisms and electrical transport near an Ising nematic quantum critical pointFeb 12 2019Electrical transport properties near an electronic Ising-nematic quantum critical point in two dimensions are of both theoretical and experimental interest. In this work, we derive a kinetic equation valid in a broad regime near the quantum critical point ... More
Suppression of Shastry-Sutherland phase driven by electronic concentration reduction in magnetically frustrated Ce$_2$Pd$_2$Sn$_{1-y}$In$_y$ alloysFeb 12 2019Shastry-Sutherland lattice was observed as alternative ground state in Rare Earth intermetallic with Mo$_2$B$_2$Fe and U$_2$Pt$_2$Sn anisotropic structures where magnetic frustration is favored. In the case of Ce$_2$Pd$_2$Sn, it was shown that such phase ... More
The role of defects in the metal-insulator transition in VO$_{2}$ and V$_2$O$_3$Feb 12 2019The vanadates VO$_2$ and V$_2$O$_3$ are prototypical examples of strongly correlated materials that exhibit a metal-insulator transition. While the phase transitions in these materials have been studied extensively, there is a limited understanding of ... More
Magnetically driven loss of centrosymmetry in metallic Pb2CoOsO6Feb 12 2019We report magnetic, transport and neutron diffraction data showing that Pb2CoOsO6, a newly synthesized metallic double-perovskite with a centrosymmetric space group at room temperature, exhibits a continuous second-order phase transition at 45 K to a ... More
Mean field approximations for short range four body interactions at $ν=3/5$Feb 12 2019Trial wavefunctions like the Moore-Read and Read-Rezayi states which minimize short range multibody interactions are candidate states for describing the fractional quantum Hall effects at filling factors $\nu = 1/2$ and $\nu = 2/5$ in the second Landau ... More
Mean field approximations for short range four body interactions at $ν=3/5$Feb 12 2019Feb 13 2019Trial wavefunctions like the Moore-Read and Read-Rezayi states which minimize short range multibody interactions are candidate states for describing the fractional quantum Hall effects at filling factors $\nu = 1/2$ and $\nu = 2/5$ in the second Landau ... More
Collective modes for quantum spin Hall insulator interacting with quantum lightFeb 12 2019We investigate the light-matter interaction between the edge state of a 2D topological insulator and quantum electromagnetic field. The interaction originates from the Zeeman term between the spin of the edge electrons and the magnetic field, and also ... More
Antiferromagnetism in RuO$_2$ as $d$-wave Pomeranchuk instabilityFeb 12 2019We present a computational study of antiferromagnetic transition in RuO$_2$. The rutile structure with the magnetic sublattices coupled by $\pi/2$-rotation leads to a spin-polarized band structure in the antiferromagnetic state, which gives rise to a ... More
Designing multi-level resistance states for multi-bit storage using half doped manganitesFeb 12 2019Designing nonvolatile multi-level resistive devices is the necessity of time to go beyond traditional one-bit storage systems, thus enhancing the storage density. Here, we explore the electronic phase competition scenario to design multi-level resistance ... More
Are many-body localized systems stable in the presence of a small bath?Feb 12 2019When pushed out of equilibrium, generic interacting quantum systems equilibrate locally and are expected to evolve towards a locally thermal description despite their unitary time evolution. Systems in which disorder competes with interactions and transport ... More
The anomalous Hall effect in non-collinear antiferromagnetic Mn$_{3}$NiN thin filmsFeb 12 2019We have studied the anomalous Hall effect (AHE) in strained thin films of the frustrated antiferromagnet Mn$_{3}$NiN. The AHE does not follow the conventional relationships with magnetization or longitudinal conductivity and is enhanced relative to that ... More
Entanglement entropy for the valence bond solid phases of two-dimensional dimerized Heisenberg antiferromagnetsFeb 12 2019We calculate the bipartite von Neumann and second R\'enyi entanglement entropies of the ground states of spin-1/2 dimerized Heisenberg antiferromagnets on a square lattice. Two distinct dimerization patterns are considered: columnar and staggered. In ... More
Monte Carlo-Mean Field study of the $t-t^{\prime}$ Hubbard model: Magnetism $\&$ Pseudogapped Metal at finite temperatureFeb 12 2019The Monte Carlo-Mean Field (MC-MF) approach rests up on deriving an effective spin fermion model containing classical and quantum degrees of freedom from an interacting many body problem. The effective model allows us to build in non-trivial thermal fluctuations ... More
Square Lattice IridatesFeb 11 2019Over the last few years, Sr$_2$IrO$_4$, a single-layer member of the Ruddlesden-Popper series iridates, has received much attention as a close analog of cuprate high-temperature superconductors. Although there is not yet firm evidence for superconductivity, ... More
Square Lattice IridatesFeb 11 2019Feb 13 2019Over the last few years, Sr$_2$IrO$_4$, a single-layer member of the Ruddlesden-Popper series iridates, has received much attention as a close analog of cuprate high-temperature superconductors. Although there is not yet firm evidence for superconductivity, ... More
Transport across junctions of pseudospin-one fermionsFeb 11 2019We study transport across ballistic junctions of materials which host pseudospin-one fermions as emergent low-energy quasiparticles. The effective low-energy Hamiltonians of such fermions are described by integer spin Weyl models. We show that current ... More
Parton construction of particle-hole-conjugate Read-Rezayi parafermion fractional quantum Hall states and beyondFeb 11 2019The Read-Rezayi (RR) parafermion states form an exotic series of non-Abelian fractional quantum Hall (FQH) states at filling $\nu = k/(k+2)$. Computationally, these wave functions are prohibitively expensive to generate for large systems. We introduce ... More
Tomonaga-Luttinger Liquid Behavior and Spinon Confinement in YbAlO$_3$Feb 11 2019Low dimensional quantum magnets are interesting because of the emerging collective behavior arising from strong quantum fluctuations. The one-dimensional (1D) S = 1/2 Heisenberg antiferromagnet is a paradigmatic example, whose low-energy excitations, ... More
Multi-faceted machine learning of competing orders in disordered interacting systemsFeb 11 2019While the non-perturbative interaction effects in the fractional quantum Hall regime can be readily simulated through exact diagonalization, it has been challenging to establish a suitable diagnostic that can label different phases in the presence of ... More
Universal low temperature theory of charged black holes with AdS$_2$ horizonsFeb 11 2019Feb 13 2019We consider the low temperature quantum theory of a charged black hole of zero temperature horizon radius $R_h$, in a spacetime which is asymptotically AdS$_{D}$ ($D > 3$) far from the horizon. At temperatures $T \ll 1/R_h$, the near-horizon geometry ... More
Universal low temperature theory of charged black holes with AdS$_2$ horizonsFeb 11 2019We consider the low temperature quantum theory of a charged black hole of zero temperature horizon radius $R_h$, in a spacetime which is asymptotically AdS$_{D}$ ($D > 3$) far from the horizon. At temperatures $T \ll 1/R_h$, the near-horizon geometry ... More
Deep autoregressive models for the efficient variational simulation of many-body quantum systemsFeb 11 2019Artificial Neural Networks were recently shown to be an efficient representation of highly-entangled many-body quantum states. In practical applications, neural-network states inherit numerical schemes used in Variational Monte Carlo, most notably the ... More
Influence of cobalt substitution on the magnetism of NiBr$_2$Feb 11 2019Co substituted Ni$_{1-x}$Co$_x$Br$_2$ (0 $\leq~x~\leq$ 1) single crystals were synthesized using vapor transport. The physical properties of the crystals were characterized by x-ray powder diffraction, magnetization, and specific heat measurements. Room ... More
Interplay of electronic and spin degrees in ferromagnetic SrRuO$_3$: anomalous softening of magnon gap and stiffnessFeb 11 2019The magnon dispersion of ferromagnetic SrRuO$_3$ was studied by inelastic neutron scattering experiments on single crystals as function of temperature. Even at low temperature the magnon modes exhibit substantial broadening pointing to strong interaction ... More
Role of static disorder and polaronic band formation on interfacial electron transfer in organic photovoltaic devicesFeb 11 2019Understanding the interfacial charge-separation mechanism in organic photovoltaics requires bridging between chemistry and physics. To elucidate this mechanism, we present the first step towards a fully quantum dynamical simulation. Working with a Hamiltonian ... More
Magnon excitations in $Cs_2CuAl_4O_8$ - a bond alternating S=1/2 spin chain with next nearest neighbor couplingFeb 11 2019A recent density functional theory (DFT) based analysis, complemented with Quantum Monte Carlo calculations revealed a highly spin-frustrating nature of the one-dimensional spin-$\frac{1}{2}$ compound $Cs_2CuAl_4O_8$ that comprises of unique bond alternations ... More
Large positive magneto-conductivity at microwave frequencies in the compensated topological insulator BiSbTeSe2Feb 11 2019The bulk electronic properties of compensated topological insulators are strongly affected by the self-organized formation of charge puddles at low temperature, but their response in the microwave frequency range is little studied. We employed broadband ... More
Quantum robustness and phase transitions of the 3D Toric Code in a fieldFeb 11 2019We study the robustness of 3D intrinsic topogical order under external perturbations by investigating the paradigmatic microscopic model, the 3D toric code in an external magnetic field. Exact dualities as well as variational calculations reveal a ground-state ... More
Existence of a critical canting angle of magnetic moments to induce multiferroicity in the Haldane spin-chain system, Tb2BaNiO5Feb 11 2019We report an unusual canted magnetism due to 3d and 4f electrons, occupying two different crystallographic sites, with its consequence to electric dipole order. This is based on neutron powder diffraction measurements on Tb2BaNiO5 (orthorhombic, Immm ... More
\textit{Ab initio} derivation of effective Hamiltonian for La$_{2}$CuO$_{4}$/La$_{1.55}$Sr$_{0.45}$CuO$_{4}$ heterostructureFeb 11 2019We formulate a method of deriving effective low-energy Hamiltonian for nonperiodic systems such as interfaces for strongly correlated electron systems by extending conventional multi-scale {\it ab initio} scheme for correlated electrons (MACE). We apply ... More
$\textit{Ab initio}$ derivation of effective Hamiltonian for La$_{2}$CuO$_{4}$/La$_{1.55}$Sr$_{0.45}$CuO$_{4}$ heterostructureFeb 11 2019Feb 13 2019We formulate a method of deriving effective low-energy Hamiltonian for nonperiodic systems such as interfaces for strongly correlated electron systems by extending conventional multi-scale $\textit{ab initio}$ scheme for correlated electrons (MACE). We ... More
Magnetization process of the insulating ferromagnetic semiconductor (Al,Fe)SbFeb 11 2019We have studied the magnetization process of the new insulating ferromagnetic semiconductor (Al,Fe)Sb by means of x-ray magnetic circular dichroism. For an optimally doped sample with 10% Fe, a magnetization was found to rapidly increase at low magnetic ... More
Holographic complexity of local quench at finite temperatureFeb 10 2019This paper is devoted to the study of the evolution of holographic complexity after a local perturbation of the system at finite temperature. We calculate the complexity using both the complexity=action and the complexity=volume conjectures and find that ... More
Anomalous thermalization by dissipation in quantum XY modelFeb 10 2019We consider the dynamics in the quantum XY model with boundary dissipation. This model after fermionization gives the topological $p$-wave superconducting model with two localized edge modes at the two ends separated from the bulk spectra by a finite ... More