18
18
Jun 27, 2018
06/18
by
Luke J. Sandilands; Yao Tian; Anjan A. Reijnders; Heung-Sik Kim; Kemp W. Plumb; Hae-Young Kee; Young-June Kim; Kenneth S. Burch
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Mott insulators with strong spin-orbit coupling have been proposed to host unconventional magnetic states, including the Kitaev quantum spin liquid. The 4$d$ system $\alpha$-RuCl$_3$ has recently come into view as a candidate Kitaev system, with evidence for unusual spin excitations in magnetic scattering experiments. We apply a combination of optical spectroscopy and Raman scattering to study the electronic structure of this material. Our measurements reveal a series of orbital excitations...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1503.07593
9
9.0
Jun 29, 2018
06/18
by
A. M. Hallas; J. A. M. Paddison; H. J. Silverstein; A. L. Goodwin; J. R. Stewart; A. R. Wildes; J. G. Cheng; J. S. Zhou; J. B. Goodenough; E. S. Choi; G. Ehlers; J. S. Gardner; C. R. Wiebe; H. D. Zhou
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eye 9
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The pyrochlore Ho2Ge2O7 is a new highly correlated spin ice material. Physical property measurements including x-ray diffraction, dc susceptibility and ac susceptibility, confirm that it shares the distinctive characteristics of other known spin ices. Polarized neutron scattering measurements on a powder sample, combined with reverse Monte Carlo (RMC) refinements, give unique information about the spin ice state in Ho2Ge2O7. RMC refinements are used to fit the powder magnetic diffuse scattering...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1603.06319
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82
Jun 27, 2018
06/18
by
Tomaz Prosen
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We review recent progress on constructing non-equilibrium steady state density operators of boundary driven locally interacting quantum chains, where driving is implemented via Markovian dissipation channels attached to the chain's ends. We discuss explicit solutions in three different classes of quantum chains, specifically, the paradigmatic (anisotropic) Heisenberg spin-1/2 chain, the Fermi-Hubbard chain, and the Lai-Sutherland spin-1 chain, and discuss universal concepts which characterize...
Topics: Nonlinear Sciences, Condensed Matter, Quantum Physics, Strongly Correlated Electrons, Statistical...
Source: http://arxiv.org/abs/1504.00783
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75
Jun 30, 2018
06/18
by
S. Wang; Z. Y. Xie; J. Chen; B. Normand; T. Xiang
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We investigate the 2- and 3-state ferromagnetic Potts models on the simple cubic lattice using the tensor renormalization group method with higher-order singular value decomposition (HOTRG). HOTRG works in the thermodynamic limit, where we use the $Z_q$ symmetry of the model, combined with a new measure for detecting the transition, to improve the accuracy of the critical point for the 2-state model by two orders of magnitude, obtaining $T_c = 4.51152469(1)$. The 3-state model is far more...
Topics: Strongly Correlated Electrons, Statistical Mechanics, Condensed Matter
Source: http://arxiv.org/abs/1405.1179
12
12
Jun 25, 2018
06/18
by
Chong Wang; Adam Nahum; T. Senthil
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eye 12
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Time reversal protected three dimensional (3D) topological paramagnets are magnetic analogs of the celebrated 3D topological insulators. Such paramagnets have a bulk gap, no exotic bulk excitations, but non-trivial surface states protected by symmetry. We propose that frustrated spin-1 quantum magnets are a natural setting for realising such states in 3D. We describe a physical picture of the ground state wavefunction for such a spin-1 topological paramagnet in terms of loops of fluctuating...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.01047
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14
Jun 26, 2018
06/18
by
Oleg Derzhko; Johannes Richter; Mykola Maksymenko
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In this review we recapitulate the basic features of the flat-band spin systems and briefly summarize earlier studies in the field. Main emphasis is made on recent developments which include results for both spin and electron flat-band models. In particular, for flat-band spin systems we highlight field-driven phase transitions for frustrated quantum Heisenberg antiferromagnets at low temperatures, chiral flat-band states, as well as the effect of a slight dispersion of a previously strictly...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1502.02729
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16
Jun 27, 2018
06/18
by
Manuel Weber; Fakher F. Assaad; Martin Hohenadler
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eye 16
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We use the continuous-time interaction expansion (CT-INT) quantum Monte Carlo method to calculate the phonon spectral function of the one-dimensional Holstein-Hubbard model at half-filling. Our results are consistent with a soft-mode Peierls transition in the adiabatic regime, and the existence of a central peak related to long-range order in the Peierls phase. We explain a previously observed feature at small momenta in terms of a hybridization of charge and phonon excitations. Tuning the...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1504.07446
12
12
Jun 28, 2018
06/18
by
M. Lohöfer; T. Coletta; D. G. Joshi; F. F. Assaad; M. Vojta; S. Wessel; F. Mila
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eye 12
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Using quantum Monte Carlo simulations along with higher-order spin-wave theory, bond-operator and strong-coupling expansions, we analyse the dynamical spin structure factor of the spin-half Heisenberg model on the square-lattice bilayer. We identify distinct contributions from the low-energy Goldstone modes in the magnetically ordered phase and the gapped triplon modes in the quantum disordered phase. In the antisymmetric (with respect to layer inversion) channel, the dynamical spin structure...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.07816
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17
Jun 28, 2018
06/18
by
Yuesheng Li; Gang Chen; Wei Tong; Li Pi; Juanjuan Liu; Zhaorong Yang; Xiaoqun Wang; Qingming Zhang
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eye 17
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YbMgGaO$_{4}$, a structurally perfect two-dimensional triangular lattice with odd number of electrons per unit cell and spin-orbit entangled effective spin-1/2 local moments of Yb$^{3+}$ ions, is likely to experimentally realize the quantum spin liquid ground state. We report the first experimental characterization of single crystal YbMgGaO$_{4}$ samples. Due to the spin-orbit entanglement, the interaction between the neighboring Yb$^{3+}$ moments depends on the bond orientations and is highly...
Topics: Superconductivity, Strongly Correlated Electrons, Condensed Matter, Materials Science
Source: http://arxiv.org/abs/1509.06766
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44
Jun 28, 2018
06/18
by
Yann Gallais; Indranil Paul
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We review the recent developments in electronic Raman scattering measurements of charge nematic fluctuations in iron-based superconductors. A simple theoretical framework of a $d$-wave Pomeranchuk transition is proposed in order to capture the salient features of the spectra. We discuss the available Raman data in the normal state of 122 iron-based systems, particularly Co doped BaFe$_2$As$_2$, and we show that the low energy quasi-elastic peak, the extracted nematic susceptibility and the...
Topics: Superconductivity, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.01319
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16
Jun 28, 2018
06/18
by
Se Kwon Kim; Jiadong Zang
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eye 16
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We study the symmetry properties of the single-band Hubbard model with general spin-orbit coupling (SOC) on the Kagome lattice. We show that the global U(1) spin-rotational symmetry is present in the Hubbard Hamiltonian owing to the inversion symmetry centered at sites. The corresponding spin Hamiltonian has, therefore, the SO(2) spin-rotational symmetry, which can be captured by including SOC non-perturbatively. The exact classical groundstates, which we obtain for arbitrary SOC, are governed...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1507.03963
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7.0
Jun 28, 2018
06/18
by
M. X. Wang; Y. Xu; L. P. He; J. Zhang; X. C. Hong; P. L. Cai; Z. B. Wang; J. K. Dong; S. Y. Li
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Low-temperature thermal conductivity measurements were performed on single crystal of PbTaSe$_2$, a noncentrosymmetric superconductor with topological bulk nodal lines in the electronic band structure. It is found that the residual linear term $\kappa_0/T$ is negligible in zero magnetic field. Furthermore, the field dependence of $\kappa_0/T$ exhibits a clear "$S$"-shape curve. These results suggest that PbTaSe$_2$ has multiple nodeless superconducting gaps. Therefore, the...
Topics: Superconductivity, Materials Science, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1511.02730
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12
Jun 29, 2018
06/18
by
Lawrence W. Cheuk; Matthew A. Nichols; Katherine R. Lawrence; Melih Okan; Hao Zhang; Ehsan Khatami; Nandini Trivedi; Thereza Paiva; Marcos Rigol; Martin W. Zwierlein
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Strong electron correlations lie at the origin of transformative phenomena such as colossal magneto-resistance and high-temperature superconductivity. Already near room temperature, doped copper oxide materials display remarkable features such as a pseudo-gap and a "strange metal" phase with unusual transport properties. The essence of this physics is believed to be captured by the Fermi-Hubbard model of repulsively interacting, itinerant fermions on a lattice. Here we report on the...
Topics: Condensed Matter, Quantum Gases, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1606.04089
4
4.0
Jun 29, 2018
06/18
by
Hidemaro Suwa; Arnab Sen; Anders W. Sandvik
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eye 4
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We study the level structure of excitations at the "deconfined" critical point separating antiferromagnetic and valence-bond-solid phases in two-dimensional quantum spin systems using the $J$-$Q$ model as an example. Energy gaps in different spin ($S$) and momentum (${\bf k}$) sectors are extracted from imaginary-time correlation functions obtained in quantum Monte Carlo simulations. We find strong quantitative evidence for deconfined linearly dispersing spinons with gapless points at...
Topics: Statistical Mechanics, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1607.05110
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4.0
Jun 29, 2018
06/18
by
Oliver DeWolfe; Steven S. Gubser; Oscar Henriksson; Christopher Rosen
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eye 4
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We use holography to compute spectral functions of certain fermionic operators in three different finite-density, zero-temperature states of ABJM theory with a broken U(1) symmetry. In each of the three states, dual to previously studied domain wall solutions of four-dimensional gauged supergravity, we find that the fermionic operators have gapped spectra. In one case the gap can be traced to the small charge of the fermions, while in the other cases it is due to a particular interaction that...
Topics: High Energy Physics - Theory, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1609.07186
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124
Jun 29, 2018
06/18
by
R. Jafari; Henrik Johannesson
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eye 124
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A quantum phase transition is generally thought to imprint distinctive characteristics on the nonequilibrium dynamics of a closed quantum system. Specifically, the Loschmidt echo after a sudden quench to a quantum critical point $-$ measuring the time dependence of the overlap between initial and time-evolved states $-$ is expected to exhibit an accelerated relaxation followed by periodic revivals. We here introduce a new exactly solvable model, the extended Su-Schrieffer-Heeger model, the...
Topics: Superconductivity, Quantum Physics, Statistical Mechanics, Condensed Matter, Strongly Correlated...
Source: http://arxiv.org/abs/1612.07046
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74
Jun 30, 2018
06/18
by
Frank Lechermann; Lewin Boehnke; Daniel Grieger; Christoph Piefke
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eye 74
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We shed light on the interplay between structure and many-body effects relevant for itinerant ferromagnetism in LaAlO$_3$/SrTiO$_3$ heterostructures. The realistic correlated electronic structure is studied by means of the (spin-polarized) charge self-consistent combination of density functional theory (DFT) with dynamical mean-field theory (DMFT) beyond the realm of static correlation effects. Though many-body behavior is also active in the defect-free interface, a ferromagnetic instability...
Topics: Materials Science, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1401.6105
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6.0
Jun 30, 2018
06/18
by
Masahiro Nozaki
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eye 6
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This is an expanded version of the short report arXiv:1401.0539, where we stud- ied the (Renyi) entanglement entropies for the excited state defined by acting a given local operator on the ground state. We introduced the (Renyi) entanglement entropies of given local operators which measure the degrees of freedom of local operators and characterize them in conformal field theories from the viewpoint of quantum entanglement. In present paper, we explain how to compute them in free massless scalar...
Topics: Quantum Physics, High Energy Physics - Theory, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1405.5875
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40
Jun 30, 2018
06/18
by
Wen-Jia Rao; Xin Wan; Guang-Ming Zhang
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eye 40
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Under an appropriate symmetric extensive bipartition in a one-dimensional symmetry protected topological (SPT) phase, a bulk critical entanglement spectrum can be obtained, resembling the excitation spectrum of the critical point separating the SPT phase from the trivial (vacuum) state. Such a critical point is beyond the standard Landau-Ginzburg-Wilson paradigm for symmetry breaking phase transitions. For the $S=1$ SPT (Haldane) phase with the Affleck-Kennedy-Lieb-Tasaki exact wave function,...
Topics: Quantum Physics, Strongly Correlated Electrons, Statistical Mechanics, Condensed Matter
Source: http://arxiv.org/abs/1406.7113
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12
Jun 26, 2018
06/18
by
V. I. Iglovikov; E. Khatami; R. T. Scalettar
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eye 12
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The sign problem is the fundamental limitation to quantum Monte Carlo simulations of the statistical mechanics of interacting fermions. Determinant quantum Monte Carlo (DQMC) is one of the leading methods to study lattice models such as the Hubbard Hamiltonian which describe strongly correlated phenomena including magnetism, metal-insulator transitions, and (possibly) exotic superconductivity. Here, we provide a comprehensive dataset on the geometry dependence of the DQMC sign problem for...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.02832
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19
Jun 26, 2018
06/18
by
Pulak Ranjan Giri; Tetsuo Deguchi
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eye 19
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We show a correspondence of all the solutions of the spin-1/2 isotropic Heisenberg model for N=12 to the rigged configurations based on the comparison of the set of Takahashi quantum numbers in lexicographical order with the set of riggings of the rigged configurations in co-lexicographical order.
Topics: Mathematics, Exactly Solvable and Integrable Systems, Strongly Correlated Electrons, Nonlinear...
Source: http://arxiv.org/abs/1501.07801
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14
Jun 27, 2018
06/18
by
Hsin-Hua Lai; Kun Yang
texts
eye 14
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In the presence of nonrelativistic supersymmetry, a sharp fermionic collective mode similar to the Goldstino mode in high-energy physics was proposed to be realized in Bose-Fermi mixtures. The Goldstino mode is relaxed (a.k.a. decays) if supersymmetry is explicitly broken, which can be revealed as the broadening of the corresponding spectral function. We find that the situation shares many similarities with the electron spin resonance in magnetic systems and adopt the well-known Kubo-Tomita...
Topics: Other Condensed Matter, Condensed Matter, Strongly Correlated Electrons, High Energy Physics -...
Source: http://arxiv.org/abs/1504.05579
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9.0
Jun 28, 2018
06/18
by
Kedar Damle
texts
eye 9
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When the constituent spins have an energetic preference to lie along an easy-axis, triangular and Kagome lattice antiferromagnets often develop long-range order that distinguishes the three sublattices of the underlying triangular Bravais lattice. In zero magnetic field, this three-sublattice order melts {\em either} in a two-step manner, {\em i.e.} via an intermediate phase with power-law three-sublattice order controlled by a temperature dependent exponent $\eta(T) \in...
Topics: Statistical Mechanics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1507.08393
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7.0
Jun 29, 2018
06/18
by
E. Ramos; R. Franco; J. Silva-Valencia; M. E. Foglio; M. S. Figueira
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eye 7
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In this work we investigate the effects of the short range magnetic correlations on the gap opening of the topological Kondo insulators. We consider an additional narrow band to the otherwise completely localized f-electrons, by adding a term to the periodic Anderson model which allows a small hopping of the localized electrons between neighboring sites of the lattice. This new model is adequate to study a novel class of intermetallic 4f and 5f orbitals materials: the Kondo topological...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1604.00422
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51
Jun 29, 2018
06/18
by
Bojan Zunkovic; Markus Heyl; Michael Knap; Alessandro Silva
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eye 51
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We theoretically study the dynamics of a transverse-field Ising chain with power-law decaying interactions characterized by an exponent $\alpha$, which can be experimentally realized in ion traps. We focus on two classes of emergent dynamical critical phenomena following a quantum quench from a ferromagnetic initial state: The first one manifests in the time averaged order parameter, which vanishes at a critical transverse field. We argue that such a transition occurs only for long-range...
Topics: Quantum Physics, Condensed Matter, Quantum Gases, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1609.08482
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108
Jun 30, 2018
06/18
by
Vincenzo Alba; Fabian Heidrich-Meisner
texts
eye 108
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We investigate the entanglement spreading in the anisotropic spin-1/2 Heisenberg (XXZ) chain after a geometric quench. This corresponds to a sudden change of the geometry of the chain or, in the equivalent language of interacting fermions confined in a box trap, to a sudden increase of the trap size. The entanglement dynamics after the quench is associated with the ballistic propagation of a magnetization wavefront. At the free fermion point (XX chain), the von-Neumann entropy S_A exhibits...
Topics: Quantum Gases, Strongly Correlated Electrons, Statistical Mechanics, Condensed Matter
Source: http://arxiv.org/abs/1402.2299
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49
Jun 30, 2018
06/18
by
A. Alexandradinata; Chen Fang; Matthew J. Gilbert; B. Andrei Bernevig
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We explore the 32 crystallographic point groups and identify topological phases of matter with robust surface modes. For n =3,4 and 6 of the C_{nv} groups, we find the first-known 3D topological insulators without spin-orbit coupling, and with surface modes that are protected only by point groups, i.e., not needing time-reversal symmetry. To describe these C_{nv} systems, we introduce the notions of (a) a halved mirror chirality: an integer invariant which characterizes half-mirror-planes in...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1402.6323
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5.0
Jun 30, 2018
06/18
by
S. Mazumdar; R. T. Clay
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eye 5
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Attempts to explain correlated-electron superconductivity have largely focused on the proximity of the superconducting state to antiferromagnetism. Yet, there exist many correlated-electron systems that exhibit insulator-superconducting transitions where the insulating state exhibits spatial broken symmetry different from antiferromagnetism. Here we focus on a subset of such compounds which are seemingly very different in which specific chemical stoichiometries play a distinct role, and small...
Topics: Superconductivity, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1403.2262
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31
Jun 30, 2018
06/18
by
Hai-Feng Li; Andrew Wildes; Binyang Hou; Cong Zhang; Berthold Schmitz; Paul Meuffels; Georg Roth; Thomas Brückel
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The magnetization, crystal structure, and thermal expansion of a nearly stoichiometric Sr$_{1.04(3)}$Er$_{2.09(6)}$O$_{4.00(1)}$ single crystal have been studied by PPMS measurements and in-house and high-resolution synchrotron X-ray powder diffraction. No evidence was detected for any structural phase transitions even up to 500 K. The average thermal expansions of lattice constants and unit-cell volume are consistent with the first-order Gr\"uneisen approximations taking into account only...
Topics: Other Condensed Matter, Strongly Correlated Electrons, Materials Science, Condensed Matter
Source: http://arxiv.org/abs/1410.6688
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19
Jun 26, 2018
06/18
by
Ravindra Pankaj; Sudhakar Yarlagadda
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eye 19
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Studying the nature and consequences of electron-phonon interaction in manganites is an area of intense ongoing research. Here, in an attempt to model charge and orbital ordering in manganites displaying C-type antiferromaganetism, we study cooperative Jahn-Teller effect in two-band one-dimensional chains in the regimes of both strong and weak electron-phonon couplings. These chains exhibit orbital ferromagnetism with only $d_{z^2}$ orbitals being occupied. At strong coupling and in the...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.06421
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14
Jun 27, 2018
06/18
by
Patrik Hlobil; Akash V. Maharaj; Pavan Hosur; M. C. Shapiro; I. R. Fisher; S. Raghu
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We propose the possible detection of broken mirror symmetries in correlated two-dimensional materials by elastotransport measurements. Using linear response theory we calculate the shearconductivity $\Gamma_{xx,xy}$, defined as the linear change of the longitudinal conductivity $\sigma_{xx}$ due to a shear strain $\epsilon_{xy}$. This quantity can only be non-vanishing when in-plane mirror symmetries are broken and we discuss how candidate states in the cuprate pseudogap regime (e.g. various...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1504.05972
10
10.0
Jun 27, 2018
06/18
by
J. Robert; E. Lhotel; G. Remenyi; S. Sahling; I. Mirebeau; C. Decorse; B. Canals; S. Petit
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In this work, we show that the zero field excitation spectra in the quantum spin ice candidate pyrochlore compound \ybti\ is a continuum characterized by a very broad and almost flat dynamical response which extends up to $1-1.5$ meV, coexisting or not with a quasi-elastic response depending on the wave-vector. The spectra do not evolve between 50 mK and 2 K, indicating that the spin dynamics is only little affected by the temperature in both the short-range correlated and ordered regimes....
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1506.01729
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15
Jun 27, 2018
06/18
by
Randy S. Fishman; Jun Hee Lee; Sándor Bordács; István Kézsmárki; Urmas Nagel; Toomas Rõõm
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A microscopic model for the room-temperature multiferroic BiFeO$_3$ that includes two Dzyaloshinskii-Moriya interactions and single-ion anisotropy along the ferroelectric polarization predicts both the zero-field spectroscopic modes as well as their splitting and evolution in a magnetic field. Due to simultaneously broken time-reversal and spatial-inversion symmetries, the absorption of light changes as the magnetic field or the direction of light propagation is reversed. We discuss three...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1506.04595
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16
Jun 28, 2018
06/18
by
Slobodan M. Radošević
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eye 16
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The method of equations of motion for spin operators in the case of O(3) Heisenberg ferromagnet is systematically analyzed starting from the effective Lagrangian. It is shown that the random phase approximation and the Callen approximation can be understood in terms of perturbation theory for type B magnons. Also, the second order approximation of Kondo and Yamaji for one dimensional ferromagnet is reduced to the perturbation theory for type A magnons. An emphasis is put on the physical...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.01974
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13
Jun 28, 2018
06/18
by
Lian-Ao Wu; Mike Guidry
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eye 13
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Graphene SU(4) quantum Hall symmetry is extended to SO(8), permitting analytical solutions for graphene in a magnetic field that break SU(4) spontaneously. We recover standard graphene SU(4) physics as one limit, but find new phases and new properties that may be relevant for understanding the ground state. The graphene SO(8) symmetry is found to be isomorphic to one that occurs extensively in nuclear structure physics, and very similar to one that describes high-temperature superconductors,...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter, Materials Science
Source: http://arxiv.org/abs/1508.03584
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17
Jun 28, 2018
06/18
by
Kazumasa Miyake; Atsushi Tsuruta
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eye 17
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On the basis of the Luttinger-Ward formalism for the thermodynamic potential, the specific heat of single-component interacting fermion systems with fixed chemical potential is compactly expressed in terms of the fully renormalized Matsubara Green function.
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.04239
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6.0
Jun 30, 2018
06/18
by
Martin Eckstein; Johan H. Mentink; Philipp Werner
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We demonstrate how electric fields with arbitrary time profile can be used to control the time-dependent parameters of spin and orbital exchange Hamiltonians. Analytic expressions for the exchange constants are derived from a time-dependent Schrieffer-Wolff transformation, and the validity of the resulting effective Hamiltonian is verified for the case of a quarter-filled two-orbital Hubbard model, by comparing to the results of a full nonequilibrium dynamical mean-field theory simulation. The...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1703.03269
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20
Jun 30, 2018
06/18
by
S. V. Syzranov; A. V. Gorshkov; V. Galitski
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We study out-of-time order correlators (OTOCs) of the form $\langle\hat A(t)\hat B(0)\hat C(t)\hat D(0)\rangle$ for a quantum system weakly coupled to a dissipative environment. Such an open system may serve as a model of, e.g., a small region in a disordered interacting medium coupled to the rest of this medium considered as an environment. We demonstrate that for a system with discrete energy levels the OTOC saturates exponentially $\propto \sum a_i e^{-t/\tau_i}+const$ to a constant value at...
Topics: Quantum Gases, Condensed Matter, Strongly Correlated Electrons, Materials Science, Mesoscale and...
Source: http://arxiv.org/abs/1704.08442
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8.0
Jun 30, 2018
06/18
by
I. S. Burmistrov; I. V. Gornyi; A. D. Mirlin
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Mesoscopic fluctuations and correlations of the local density of states are studied near metal-insulator transitions in disordered interacting electronic systems. We show that the multifractal behavior of the local density of states survives in the presence of Coulomb interaction. We calculate the spectrum of multifractal exponents in $2+\epsilon$ spatial dimensions for symmetry classes characterized by broken (partially or fully) spin-rotation invariance and show that it differs from that in...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1412.3306
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6.0
Jun 30, 2018
06/18
by
Harald O. Jeschke; Francesc Salvat-Pujol; Elena Gati; Nguyen Hieu Hoang; Bernd Wolf; Michael Lang; John A. Schlueter; Roser Valenti
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We investigate the structural, electronic and magnetic properties of the newly synthesized mineral barlowite Cu4(OH)6FBr which contains Cu2+ ions in a perfect kagome arrangement. In contrast to the spin-liquid candidate herbertsmithite ZnCu3(OH)6Cl2, kagome layers in barlowite are perfectly aligned due to the different bonding environments adopted by F- and Br- compared to Cl-. We perform density functional theory calculations to obtain the Heisenberg Hamiltonian parameters of Cu4(OH)6FBr which...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1412.4668
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11
Jun 26, 2018
06/18
by
Guang-Hua Liu; Wen-Long You; Wei Li; Gang Su
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eye 11
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Quantum phase transitions (QPTs) and the ground-state phase diagram of the spin-1/2 Heisenberg-Ising alternating chain (HIAC) with uniform Dzyaloshinskii-Moriya (DM) interaction are investigated by a matrix-product-state (MPS) method. By calculating the odd- and even-string order parameters, we recognize two kinds of Haldane phases, i.e., the odd- and even-Haldane phases. Furthermore, doubly degenerate entanglement spectra on odd and even bonds are observed in odd- and even-Haldane phases,...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1502.01821
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17
Jun 27, 2018
06/18
by
A. Jesche; L. Ke; J. L. Jacobs; B. Harmon; R. S. Houk; P. C. Canfield
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Substantial amounts of the transition metals Mn, Fe, Co, and Ni can be substituted for Li in single crystalline Li$_2$(Li$_{1-x}T_x$)N. Isothermal and temperature-dependent magnetization measurements reveal local magnetic moments with magnitudes significantly exceeding the spin-only value. The additional contributions stem from unquenched orbital moments that lead to rare-earth-like behavior of the magnetic properties. Accordingly, extremely large magnetic anisotropies have been found. Most...
Topics: Condensed Matter, Strongly Correlated Electrons, Materials Science
Source: http://arxiv.org/abs/1503.02501
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6.0
Jun 30, 2018
06/18
by
Tian-Heng Han; Robin Chisnell; Craig J. Bonnoit; Danna E. Freedman; Vivien S. Zapf; Neil Harrison; Daniel G. Nocera; Yasu Takano; Young S. Lee
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We report measurements of the specific heat and magnetization of single crystal samples of the spin-1/2 kagome compound ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$ (herbertsmithite), a promising quantum spin-liquid candidate, in high magnetic fields and at low temperatures. The magnetization was measured up to $\mu_{0}H$ = 55 T at $T$ = 0.4 K, showing a saturation of the weakly interacting impurity moments in fields above $\sim10$ T. The specific heat was measured down to $T < 0.4$ K in magnetic fields up...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1402.2693
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20
Jun 26, 2018
06/18
by
Daniel Guterding; Steffen Backes; Harald O. Jeschke; Roser Valenti
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Recently, KFe$_2$As$_2$ was shown to exhibit a structural phase transition from a tetragonal to a collapsed tetragonal phase under applied pressure of about $15~\mathrm{GPa}$. Surprisingly, the collapsed tetragonal phase hosts a superconducting state with $T_c \sim 12~\mathrm{K}$, while the tetragonal phase is a $T_c \leq 3.4~\mathrm{K}$ superconductor. We show that the key difference between the previously known non-superconducting collapsed tetragonal phase in AFe$_2$As$_2$ (A= Ba, Ca, Eu,...
Topics: Superconductivity, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1501.03068
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13
Jun 26, 2018
06/18
by
Fabien Tran; Markus Betzinger; Peter Blaha; Stefan Blügel
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The exact-exchange (EXX) potential, which is obtained by solving the optimized-effective potential (OEP) equation, is compared to various approximate semilocal exchange potentials for a set of selected solids (C, Si, BN, MgO, Cu$_{2}$O, and NiO). This is done in the framework of the linearized augmented plane-wave method, which allows for a very accurate all-electron solution of electronic structure problems in solids. In order to assess the ability of the semilocal potentials to approximate...
Topics: Materials Science, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.07105
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10.0
Jun 27, 2018
06/18
by
V. K. Anand; D. C. Johnston
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Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility \chi versus temperature T, isothermal magnetization M versus magnetic field H, specific heat Cp(T) and electrical resistivity \rho(T) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type...
Topics: Condensed Matter, Strongly Correlated Electrons, Materials Science
Source: http://arxiv.org/abs/1503.06074
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18
Jun 28, 2018
06/18
by
J. Gonzalez
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We investigate the strong-coupling phases that may arise in 3D Dirac and Weyl semimetals under the effect of the long-range Coulomb interaction, considering the many-body theory of these electron systems as a variant of the conventional fully relativistic Quantum Electrodynamics (QED). For this purpose, we apply two different nonperturbative approaches, consisting in the sum of ladder diagrams and taking the limit of a large number N of fermion flavors. We benefit from the renormalizability...
Topics: High Energy Physics - Phenomenology, Mesoscale and Nanoscale Physics, Strongly Correlated...
Source: http://arxiv.org/abs/1509.00210
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12
Jun 28, 2018
06/18
by
G. Baskaran
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Paired valence electrons forming covalent bonds in molecues are confined cooper pair correlations. High pressure dissociates molecules in solid H2S, SiH4, H2 etc. and form extended structures. However, valence electrons are resilient and continue to bond and sometimes resonate. It is suggested that some structures contain emergent Mott insulators (EMI) and support superconductivity and other phases, under special conditions. In pressurized solid H2S, we propose presence of a sublattice of...
Topics: Superconductivity, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1507.03921
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66
Jun 30, 2018
06/18
by
A. Alexandradinata; B. Andrei Bernevig
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In this lecture for the Nobel symposium, we review previous research on a class of translational-invariant insulators without spin-orbit coupling. These may be realized in intrinsically spinless systems such as photonic crystals and ultra-cold atoms. Some of these insulators have no time-reversal symmetry as well, i.e., the relevant symmetries are purely crystalline. Nevertheless, topological phases exist which are distinguished by their robust surface modes. To describe these phases, we...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1411.3338
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5.0
Jun 30, 2018
06/18
by
K. V. Reich; M. Schecter; B. I. Shklovskii
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We study potential and electron density depth profiles in accumulation, inversion and depletion layers in crystals with large and nonlinear dielectric response such as $\mathrm{SrTiO_3}$. We describe the lattice dielectric response using the Landau-Ginzburg free energy expansion. In accumulation and inversion layers we arrive at new nonlinear dependencies of the width $d$ of the electron gas on applied electric field $D_0$. Particularly important is the predicted electron density profile of...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1412.6024
