9
9.0
Jun 29, 2018
06/18
by
Yasir Iqbal; Didier Poilblanc; Federico Becca
texts
eye 9
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In a recent paper [arXiv:1601.02165], Tao Li claimed that a gapped $\mathbb{Z}_2$ spin liquid, obtained using projected Gutzwiller fermionic wave functions, can be stabilized in the Heisenberg model on the kagome lattice. We perform very accurate variational calculations and confirm with unprecedented accuracy the fact, that the $\mathbb{Z}_{2}$ spin liquid is a local energy minimum that goes away with system size, thus reaffirming the scenario of a gapless $U(1)$ Dirac spin liquid ground state.
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1606.02255
4
4.0
Jun 29, 2018
06/18
by
P. A. Maksimov; M. E. Zhitomirsky; A. L. Chernyshev
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eye 4
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We investigate field-induced transformations in the dynamical response of the $XXZ$ model on the triangular lattice that are associated with the anharmonic magnon coupling and decay phenomena. A set of concrete theoretical predictions is made for a close physical realization of the spin-1/2 $XXZ$ model, Ba$_3$CoSb$_2$O$_9$. We demonstrate that dramatic modifications in magnon spectrum must occur in low out-of-plane fields that are easily achievable for this material. The hallmark of the effect...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1607.08238
3
3.0
Jun 29, 2018
06/18
by
S. Holbein; M. Ackermann; L. Chapon; P. Steffens; A. Gukasov; A. Sazonov; O. Breunig; Y. Sanders; P. Becker; L. Bohaty; T. Lorenz; M. Braden
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eye 3
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The crystal structure of the double tungstate NaFe(WO$_4$)$_2$ arises from that of the spin-driven multiferroic MnWO$_4$ by inserting non-magnetic Na layers. NaFe(WO$_4$)$_2$ exhibits a three-dimensional incommensurate spin-spiral structure at low temperature and zero magnetic field, which, however, competes with commensurate order induced by magnetic field. The incommensurate zero-field phase corresponds to the condensation of a single irreducible representation but it does not imply...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1609.01849
4
4.0
Jun 29, 2018
06/18
by
D. M. Kennes; J. C. Pommerening; J. Diekmann; C. Karrasch; V. Meden
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We study the expectation values of observables and correlation functions at long times after a global quantum quench. Our focus is on metallic (`gapless') fermionic many-body models and small quenches. The system is prepared in an eigenstate of an initial Hamiltonian, and the time evolution is performed with a final Hamiltonian which differs from the initial one in the value of one global parameter. We first derive general relations between time-averaged expectation values of observables as...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1610.03284
4
4.0
Jun 29, 2018
06/18
by
Jose A. Riera
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eye 4
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A system composed of a conducting planar strip with Rashba spin-orbit coupling (RSOC), magnetically coupled to a layer of localized magnetic moments, at equilibrium, is studied within a microscopic Hamiltonian with numerical techniques at zero temperature in the clean limit. In particular, transport properties for the cases of ferromagnetic (FM) and antiferromagnetic (AFM) coupled layers are computed in linear response on strips of varying width. Some behaviors observed for these properties are...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1610.09399
4
4.0
Jun 29, 2018
06/18
by
Christopher B. Bishop; Adriana Moreo; Elbio Dagotto
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eye 4
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The bicollinear antiferromagnetic order experimentally observed in FeTe is shown to be stabilized by the coupling $\tilde g_{12}$ between monoclinic lattice distortions and the spin-nematic order parameter with $B_{\rm 2g}$ symmetry, within a three-orbital spin-fermion model studied with Monte Carlo techniques. A finite but small value of $\tilde g_{12}$ is required, with a concomitant lattice distortion compatible with experiments, and a tetragonal-monoclinic transition strongly first order....
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1606.00904
14
14
Jun 26, 2018
06/18
by
B. Dalla Piazza; M. Mourigal; N. B. Christensen; G. J. Nilsen; P. Tregenna-Piggott; T. G. Perring; M. Enderle; D. F. McMorrow; D. A. Ivanov; H. M. Rønnow
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eye 14
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The square-lattice quantum Heisenberg antiferromagnet displays a pronounced anomaly of unknown origin in its magnetic excitation spectrum. The anomaly manifests itself only for short wavelength excitations propagating along the direction connecting nearest neighbors. Using polarized neutron spectroscopy, we have fully characterized the magnetic fluctuations in the model metal-organic compound CFTD, revealing an isotropic continuum at the anomaly indicative of fractional excitations. A...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.01767
9
9.0
Jun 26, 2018
06/18
by
Jian-Xin Zhu; R. C. Albers; K. Haule; J. M. Wills
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eye 9
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Based on its condensed-matter properties, crystal structure, and metallurgy, which includes a phase diagram with six allotropic phases, plutonium is one of the most complicated pure elements in its solid state. Its anomalous properties, which are indicative of a very strongly correlated state, are related to its special position in the periodic table, which is at the boundary between the light actinides that have itinerant 5$f$ electrons and the heavy actinides that have localized 5$f$...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.06252
14
14
Jun 26, 2018
06/18
by
N. P. Konstantinidis
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eye 14
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We investigate the rate of thermalization of local operators in the one-dimensional anisotropic antiferromagnetic Heisenberg model with next-nearest neighbor interactions that break integrability. This is done by calculating the scaling of the difference of the diagonal and canonical thermal ensemble values as function of system size, and by directly calculating the time evolution of the expectation values of the operators with the Chebyshev polynomial expansion. Spatial and spin symmetry is...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1502.06320
21
21
Jun 27, 2018
06/18
by
B. Samantaray; N. Khan; A. Midya; P. Mandal; S. Ravi
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eye 21
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We present results on resistivity ($\rho$), magnetization ($M$), thermal conductivity ($\kappa$), magnetostriction ($\frac{\Delta L}{L(0)}$) and specific heat ($C_{p}$) of charge-orbital ordered antiferromagnetic Nd$_{0.8}$Na$_{0.2}$MnO$_{3}$ compound. Magnetic field-induced antiferromagnetic/charge-orbital ordered insulating to ferromagnetic metallic transition leads to giant magnetothermal conductivity and magnetostriction effect. The low-temperature irreversibility behavior in $\rho$, $M$,...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1503.06552
8
8.0
Jun 27, 2018
06/18
by
T. P. Cysne; M. B. Silva Neto
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eye 8
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We obtain the complete phase diagram of the antiferromagnetic $J_{1}$-$J_{2}$ model, $0\leq \alpha = J_2/J1 \leq 1$, within the framework of the $O(N)$ nonlinear sigma model. We find two magnetically ordered phases, one with N\' eel order, for $\alpha \leq 0.4$, and another with collinear order, for $\alpha\geq 0.6$, separated by a nonmagnetic region, for $0.4\leq \alpha \leq 0.6$, where a gapped spin liquid is found. The transition at $\alpha=0.4$ is of the second order while the one at...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1504.01334
12
12
Jun 27, 2018
06/18
by
Didier Poilblanc; J. Ignacio Cirac; Norbert Schuch
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eye 12
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Topological chiral phases are ubiquitous in the physics of the Fractional Quantum Hall Effect. Non-chiral topological spin liquids are also well known. Here, using the framework of projected entangled pair states (PEPS), we construct a family of chiral spin liquids on the square lattice which are generalized spin-1/2 Resonating Valence Bond (RVB) states obtained from deformed local tensors with $d+i\, d$ symmetry. On a cylinder, we construct four topological sectors with even or odd number of...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1504.05236
7
7.0
Jun 28, 2018
06/18
by
V. Vildosola; L. V. Pourovskii; L. O. Manuel; P. Roura-Bas
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eye 7
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We assess the reliability of the one-crossing approximation (OCA) approach in quantitative description of the Mott transition in the framework of the dynamical mean field theory (DMFT). The OCA approach has been applied in the conjunction with DMFT to a number of heavy-fermion, actinide, transition metal compounds, and nanoscale systems. However, several recent studies in the framework of impurity models pointed out to serious deficiencies of OCA and raised questions regarding its reliability....
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1506.06145
3
3.0
Jun 30, 2018
06/18
by
Philippe Corboz; Frederic Mila
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eye 3
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Using infinite projected entangled-pair states (iPEPS), we show that the Shastry-Sutherland model in an external magnetic field has low-magnetization plateaus which, in contrast to previous predictions, correspond to crystals of bound states of triplets, and {\it not} to crystals of triplets. The first sizable plateaus appear at magnetization 1/8, 2/15 and 1/6, in agreement with experiments on the orthogonal-dimer antiferromagnet SrCu$_2$(BO$_3$)$_2$, and they can be naturally understood as...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1401.3778
22
22
Jun 28, 2018
06/18
by
P. P. Baruselli; R. Requist; A. Smogunov; M. Fabrizio; E. Tosatti
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eye 22
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The Kondo zero bias anomaly of Co adatoms probed by scanning tunneling microscopy is known to depend on the height of the tip above the surface, and this dependence is different on different low index Cu surfaces. On the (100) surface, the Kondo temperature first decreases then increases as the tip approaches the adatom, while on the (111) surface it is virtually unaffected. These trends are captured by combined density functional theory and numerical renormalization group (DFT+NRG)...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1507.00253
11
11
Jun 28, 2018
06/18
by
Mohammad Pouranvari; Kun Yang
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eye 11
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We examine the real space renormalization group method of finding \textit{excited eigenstate} (RSRG-X) of the XX spin-1/2 chain, from entanglement perspectives. Eigenmodes of entanglement Hamiltonian, especially the maximally entangled mode and corresponding entanglement energies are studied and compared with predictions of RSRG-X. Our numerical results demonstrate the accuracy of the RSRG-X method in the strong disorder limit, and quantify its error when applied to weak disorder regime....
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.05829
4
4.0
Jun 30, 2018
06/18
by
David J. Luitz; Xavier Plat; Nicolas Laflorencie; Fabien Alet
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eye 4
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We present a method for improving measurements of the entanglement R\'enyi entropies in quantum Monte Carlo simulations by relating them with measurements of participation R\'enyi entropies. Exploiting the capability of building improved estimators for the latter allows to obtain very good estimates for entanglement R\'enyi entropies. When considering a full system instead of a bipartition, the method can be further ameliorated providing access to the thermodynamic R\'enyi entropies with high...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1405.7391
3
3.0
Jun 30, 2018
06/18
by
Tommaso Coletta; Sergey E. Korshunov; Frédéric Mila
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eye 3
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We investigate the zero-temperature phase diagram of the fully frustrated transverse field Ising model on the square lattice both in the classical limit and in the presence of quantum fluctuations. At the classical level (the limit of infinite spin $S$), we find that upon decreasing the transverse field $\Gamma$ this model exhibits a phase transition from the fully polarized state into an eight-fold degenerate translational symmetry breaking state. This phase can be identified to correspond to...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1408.3515
9
9.0
Jun 27, 2018
06/18
by
Sant Kumar; Umesh K. Yadav; T. Maitra; Ishwar Singh
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eye 9
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The spin-dependent Falicov-Kimball model (FKM) is studied on a triangular lattice using numerical diagonalization technique and Monte-Carlo simulation algorithm. Magnetic properties have been explored for different values of parameters: on-site Coulomb correlation $U$, exchange interaction $J$ and filling of electrons. We have found that the ground state configurations exhibit long range Ne\`el order, ferromagnetism or a mixture of both as $J$ is varied. The magnetic moments of itinerant ($d$)...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1504.03429
11
11
Jun 28, 2018
06/18
by
O. I. Utesov; A. V. Sizanov; A. V. Syromyatnikov
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eye 11
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We present a theory describing spiral magnets with Dzyaloshinskii-Moriya interaction (DMI) subject to bond disorder at small concentration $c$ of defects. It is assumed that both DMI and exchange coupling are changed on imperfect bonds. Qualitatively the same physical picture is obtained in two models which are considered in detail: B20 cubic helimagnets and layered magnets in which DMI leads to a long-period spiral ordering perpendicular to layers. We find that the distortion of the spiral...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1507.01139
15
15
Jun 28, 2018
06/18
by
Shunsaku Kitagawa; Taishi Sekiya; Shingo Araki; Tatsuo C. Kobayashi; Kenji Ishida; Takashi Kambe; Takumi Kimura; Naoki Nishimoto; Kazutaka Kudo; Minoru Nohara
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eye 15
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The mineral tetrahedrite Cu$_{12}$Sb$_{4}$S$_{13}$ exhibits a first-order metal--insulator transition (MIT) at $T_{\rm MI}$ = 85 K and ambient pressure. We measured the $^{63}$Cu-NMR at ambient pressure and the resistivity and magnetic susceptibility at high pressures. $^{63}$Cu-NMR results indicate a nonmagnetic insulating ground state in this compound. The MIT is monotonically suppressed by pressure and disappears at $\sim1.0$ GPa. Two other anomalies are observed in the resistivity...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.03933
15
15
Jun 28, 2018
06/18
by
A. L. de Oliveira; C. M. Chaves; N. A. de Oliveira; A. Troper
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eye 15
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We study the formation of local magnetic moments and magnetic hyperfine fields at an \textit{s-p} impurity diluted in intermetallic Laves phases compounds $R$Ni$_{2}$ ($R$ = Nd, Sm, Gd, Tb, Dy) at finite temperatures. We start with a clean host and later the impurity is introduced. The host has two-coupled ($R$ and Ni) sublattice Hubbard Hamiltonians but the Ni sublattice can be disregarded because its $\textit{d}$ band, being full, is magnetically ineffective. Also, the effect of the...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1508.05969
4
4.0
Jun 28, 2018
06/18
by
Lin Li; Zhan Cao; Tie-Feng Fang; Hong-Gang Luo; Wei-Qiang Chen
texts
eye 4
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Motivated by experimental observation of the Kondo-enhanced Andreev transport [R. S. Deacon \textit{et al.}, PRB \textbf{81}, 121308(R) (2010)] in a hybrid normal metal-quantum dot-superconductor (N-QD-S) device, we theoretically study the Kondo effect in such a device and clarify the different roles played by the normal and superconducting leads. Due to the Andreev reflection in a QD-S system, a pair of Andreev energy levels form in the superconducting gap, which is able to carry the magnetic...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1512.03856
6
6.0
Jun 29, 2018
06/18
by
Alain Audouard; Jean-Yves Fortin; David Vignolles; Vladimir N. Laukhin; Nataliya D. Kushch; Eduard B. Yagubskii
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eye 6
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De Haas-van Alphen oscillations of the organic metal \k{appa}-(ET) 2 Cu(SCN) 2 have been measured up to 55 T at liquid helium temperatures. The Fermi surface of this charge transfer salt is a textbook example of linear chain of orbits coupled by magnetic breakdown. Accordingly, the oscillation spectrum is composed of linear combinations of the frequencies linked to the $\alpha$ and magnetic breakdown-induced $\beta$ orbits. The field and temperature dependence of all the observed Fourier...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1605.02449
5
5.0
Jun 30, 2018
06/18
by
Aaram J. Kim; M. Y. Choi; Gun Sang Jeon
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eye 5
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We consider a Mott transition of the Hubbard model in infinite dimensions. The dynamical mean- field theory is employed in combination with a continuous-time quantum Monte Carlo (CTQMC) method for an accurate description at low temperatures. From the double occupancy and the energy density, which are directly measured from the CTQMC method, we construct the phase diagram. We pay particular attention to the construction of the first-order phase transition line (PTL) in the co- existence region...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1405.4512
4
4.0
Jun 30, 2018
06/18
by
Hiroaki T. Ueda
texts
eye 4
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Frustration can introduce more-than-two minima in a spin dispersion relation even in a fully polarized magnet under high magnetic field. We generally discuss, on the fully polarized phase, the possibility of the chiral symmetry breaking where the number of magnons pumped by finite temperature deviates to one side of minima. We study this phase by constructing the Ginzburg-Landau energy which is controlled by the external magnetic field and interactions between magnons near the dispersion...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1406.2617
9
9.0
Jun 26, 2018
06/18
by
Shinichi Takemura; Nayuta Takemori; Akihisa Koga
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eye 9
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We study the extended Anderson model on the two-dimensional Penrose lattice, combining the real-space dynamical mean-field theory with the non-crossing approximation. It is found that the Coulomb repulsion between localized and conduction electrons does not induce a valence transition, but the crossover between the Kondo and mixed valence states in contrast to the conventional periodic system. In the mixed-valence region close to the crossover, nontrivial valence distributions appear...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1502.03907
20
20
Jun 26, 2018
06/18
by
Ye Zhuang; Hitesh J. Changlani; Norm M. Tubman; Taylor L. Hughes
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eye 20
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Parafermions are exotic quasiparticles with non-Abelian fractional statistics that can be realized and stabilized in 1-dimensional models that are generalizations of the Kitaev p-wave wire. We study the simplest generalization, i.e. the $Z_3$ parafermionic chain. Using a Jordan-Wigner transform we focus on the equivalent three-state chiral clock model, and study its rich phase diagram using the density matrix renormalization group technique. We perform our analyses using quantum entanglement...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1502.05049
7
7.0
Jun 29, 2018
06/18
by
G. Simutis; S. Gvasaliya; N. S. Beesetty; T. Yoshida; J. Robert; S. Petit; A. I. Kolesnikov; M. B. Stone; F. Bourdarot; H. C. Walker; D. T. Adroja; O. Sobolev; C. Hess; T. Masuda; A. Revcolevschi; B. Büchner; A. Zheludev
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eye 7
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The low energy magnetic excitation spectrum of the Heisenberg antiferromagnetic $S = 1/2$ chain system Sr$_2$CuO$_3$ with Ni- and Ca-impurities is studied by neutron spectroscopy. In all cases, a defect-induced spectral pseudogap is observed and shown to scale proportionately to the number of scattering centers in the spin chains.
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.04183
10
10.0
Jun 29, 2018
06/18
by
M. L. Baez; R. A. Borzi
texts
eye 10
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We study the three-dimensional Kasteleyn transition in both nearest neighbours and dipolar spin ice models using an algorithm that conserves the number of excitations. We first limit the interactions range to nearest neighbours to test the method in the presence of a field applied along $[100]$, and then focus on the dipolar spin ice model. The effect of dipolar interactions, which is known to be greatly self screened at zero field, is particularly strong near full polarization. It shifts the...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.06424
3
3.0
Jun 29, 2018
06/18
by
Robert Schade; Peter E. Blöchl
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eye 3
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The exact reduced density-matrix functional for interacting electrons can in principle be calculated from Levy's constrained search formalism. In order to make the problem tractable it is divided into impurity problems, where the impurity captures the interaction. A method, called the adaptive cluster approximation (ACA), is proposed to concentrate the effect of the bath to a small cluster around the impurity. A unitary transformation between the bath basis states is tailored to minimize the...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1612.06692
7
7.0
Jun 30, 2018
06/18
by
Haruka Taniguchi; Daichi Kimura; Michiaki Matsukawa; Tasuku Inomata; Satoru Kobayashi; Shigeki Nimori; Ramanathaan Suryanarayanan
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eye 7
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We investigated slow relaxations of the magnetostriction and residual magnetostriction of the phase-separated system (Eu$_{1-x}$Gd$_{x}$)$_{0.6}$Sr$_{0.4}$MnO$_3$, in which the metamagnetic transition from a paramagnetic insulating state to a ferromagnetic metallic state is accompanied by a lattice shrinkage. The relaxations are well fitted by a stretched exponential function, suggesting the strong frustraction between the double exchange interaction and Jahn-Teller effect. We have revealed...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1703.10392
3
3.0
Jun 30, 2018
06/18
by
Andrew J. A. James; Robert M. Konik; Philippe Lecheminant; Neil J. Robinson; Alexei M. Tsvelik
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eye 3
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We review two important non-perturbative approaches for extracting the physics of low-dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of conformal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1703.08421
3
3.0
Jun 30, 2018
06/18
by
J. S. Hall; T. Timusk
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eye 3
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We summarize existing optical data of URu$_2$Si$_2$ to clarify the nature of the hidden order transition in this heavy fermion metal. Hybridization develops between 50 K and 17.5 K, and a coherent Drude peak emerges which mirrors the changes in the dc resistivity. The Drude weight indicates that there is little change in the effective mass of these carriers in this temperature range. In addition, there is a flat background conductivity that develops a partial hybridization gap at 10 meV as the...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1404.7093
5
5.0
Jun 29, 2018
06/18
by
Yaroslav Pavlyukh
texts
eye 5
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A unified diagrammatic treatment single and double electron photoemission currents is presented. The irreducible lesser density-density response function is the starting point of these derivations. Diagrams for higher order processes in which several electrons are observed in coincidence can likewise be obtained. For physically relevant situations in which the photoemission cross-section can be written as the Fermi Golden rule, the diagrams from the nonequilibrium Green's function approach can...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1601.04278
3
3.0
Jun 29, 2018
06/18
by
M. Dressel; P. Lazic; A. Pustogow; E. Zhukova; B. Gorshunov; J. A. Schlueter; O. Milat; B. Gumhalter; S. Tomic
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eye 3
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The dimer Mott insulator $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ exhibits unusual electrodynamic properties. Numerical investigations of the electronic ground state and the molecular and lattice vibrations reveal the importance of the Cu$_2$(CN)$_3^-$ anion network coupled to the BEDT-TTF molecules: The threefold cyanide coordination of copper and linkage isomerism in the anion structure cause a loss of symmetry, frustration, disorder, and domain formation. Our findings consistently explain the...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1601.04926
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22
Jun 27, 2018
06/18
by
Carlos A. Jiménez-Hoyos; Gustavo E. Scuseria
texts
eye 22
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We introduce a mean-field and perturbative approach, based on clusters, to describe the ground state of fermionic strongly-correlated systems. In cluster mean-field, the ground state wavefunction is written as a simple tensor product over optimized cluster states. The optimization of the single-particle basis where the cluster mean-field is expressed is crucial in order to obtain high-quality results. The mean-field nature of the ansatz allows us to formulate a perturbative approach to account...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1505.05909
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13
Jun 27, 2018
06/18
by
Raul A. Santos; D. B. Gutman
texts
eye 13
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Anderson's localization on the edge of two dimensional time reversal (TR) topological insulator (TI) is studied. For the non-interacting case the topological protection acts accordingly to the $\mathbb{Z}_2$ classification, leading to conducting and insulating phases for odd and even fillings respectively. In the presence of repulsive interaction the phase diagram is notably changed. We show that for sufficiently strong values of the interaction the zero temperature fixed point of the TI is...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1505.05979
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7.0
Jun 27, 2018
06/18
by
Luca F. Tocchio; Federico Arrigoni; Sandro Sorella; Federico Becca
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eye 7
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We study the Mott metal-insulator transition in the two-band Hubbard model with different hopping amplitudes $t_1$ and $t_2$ for the two orbitals on the two-dimensional square lattice by using {\it non-magnetic} variational wave functions, similarly to what has been considered in the limit of infinite dimensions by dynamical mean-field theory. We work out the phase diagram at half filling (i.e., two electrons per site) as a function of $R=t_2/t_1$ and the on-site Coulomb repulsion $U$, for two...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1505.07006
5
5.0
Jun 29, 2018
06/18
by
J. D. Denlinger; Sooyoung Jang; G. Li; L. Chen; B. J. Lawson; T. Asaba; C. Tinsman; F. Yu; Kai Sun; J. W. Allen; C. Kurdak; Dae-Jong Kim; Z. Fisk; Lu Li
texts
eye 5
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The mixed valent compound SmB6 is of high current interest as the first candidate example of topologically protected surface states in a strongly correlated insulator and also as a possible host for an exotic bulk many-body state that would manifest properties of both an insulator and a metal. Two different de Haas van Alphen (dHvA) experiments have each supported one of these possibilities, while angle resolved photoemission spectroscopy (ARPES) for the (001) surface has supported the first,...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1601.07408
4
4.0
Jun 29, 2018
06/18
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Makoto Naka; Sumio Ishihara
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Quantum entanglement effects between the electronic spin and charge degrees of freedom are examined in an organic molecular solid, termed a dimer-Mott insulating system, in which molecular dimers are arranged in a crystal as fundamental units. A low energy effective model includes an antisymmetric exchange interaction, as one of the dominant magnetic interactions. This interaction favors a 90 degree spin configuration, and competes with the Heisenberg-type exchange interaction. Stabilities of...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1602.00103
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4.0
Jun 29, 2018
06/18
by
Stephan Hesselmann; Stefan Wessel
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The scaling of the transition temperature into an ordered phase close to a quantum critical point as well as the order parameter fluctuations inside the quantum critical region provide valuable information about universal properties of the underlying quantum critical point. Here, we employ quantum Monte Carlo simulations to examine these relations in detail for two-dimensional quantum systems that exhibit a finite-temperature Ising-transition line in the vicinity of a quantum critical point...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1602.02096
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3.0
Jun 29, 2018
06/18
by
Andrew K. Mitchell; L. A. Landau; L. Fritz; E. Sela
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We study a charge two-channel Kondo model, demonstrating that recent experiments [Iftikhar et al, Nature 526, 233 (2015)] realize an essentially perfect quantum simulation -- not just of its universal physics, but also nonuniversal effects away from the scaling limit. Numerical renormalization group (NRG) calculations yield conductance lineshapes encoding RG flow to a critical point involving a free Majorana fermion. By mimicking the experimental protocol, the experimental curve is reproduced...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1602.02093
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5.0
Jun 29, 2018
06/18
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Xiao Yan Xu; K. S. D. Beach; Kai Sun; F. F. Assaad; Zi Yang Meng
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Interaction-driven topological phase transitions in Dirac semimetals are investigated by means of large-scale quantum Monte Carlo (QMC) simulations. The interaction among Dirac fermions is introduced by coupling them to Ising spins that realize the quantum dynamics of the two-dimensional transverse field Ising model. The ground state phase diagram, in which the tuning parameters are the transverse field and the coupling between fermion and Ising spins, is determined. At weak and intermediate...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1602.07150
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Jun 28, 2018
06/18
by
S. Guitteny; I. Mirebeau; P. Dalmas de Réotier; C. Colin; P. Bonville; F. Porcher; B. Grenier; C. Decorse; S. Petit
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We have studied the spin correlations with $\bf{k}$= ($\frac12$, $\frac12$, $\frac12$) propagation vector which appear below 0.4\, K in \tbti\ spin liquid by combining powder neutron diffraction and specific heat on Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ samples with $x$=0, 0.01, -0.01. The $\bf{k}$= ($\frac12$, $\frac12$, $\frac12$) order clearly appears on all neutron patterns by subtracting a pattern at 1.2(1)\,K. Refining the subtracted patterns at 0.07\,K yields two possible spin structures, with...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1506.07604
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3.0
Jun 29, 2018
06/18
by
Yasutami Takada
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By comparing two expressions for the polarization function given in terms of two different local-field factors, G_+(q,iw) and G_s(q,iw), we have derived the kinetic-energy-fluctuation (or sixth-power) sum rule for the momentum distribution function n(p) in the three-dimensional electron gas. With use of this sum rule, together with the total-number (or second-power) and the kinetic-energy (or fourth-power) sum rules, we have obtained n(p) in the low-density electron gas at negative...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.06479
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3.0
Jun 29, 2018
06/18
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A. Zorko; M. Herak; M. Gomilšek; J. van Tol; M. Velázquez; P. Khuntia; F. Bert; P. Mendels
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Employing complementary torque magnetometry and electron spin resonance on single crystals of herbertsmithite, the closest realization to date of a quantum kagome antiferromagnet featuring a spin-liquid ground state, we provide novel insight into different contributions to its magnetism. At low temperatures, two distinct types of defects with different magnetic couplings to the kagome spins are found. Surprisingly, their magnetic response contradicts the three-fold symmetry of the ideal kagome...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1612.02923
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3.0
Jun 29, 2018
06/18
by
Ammar Nejati; Katinka Ballmann; Johann Kroha
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In a Kondo lattice, the spin exchange coupling between a local spin and the conduction electrons acquires nonlocal contributions due to conduction electron scattering from surrounding local spins and the subsequent RKKY interaction. It leads to a hitherto unrecognized interference of Kondo screening and the RKKY interaction beyond the Doniach scenario. We develop a renormalization group theory for the RKKY-modified Kondo vertex. The Kondo temperature, $T_K(y)$, is suppressed in a universal way,...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1612.03338
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3.0
Jun 29, 2018
06/18
by
Lei Gu; Hua-Hua Fu; Ruqian Wu
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The control of the spin-Seebeck current is still a challenging task for the development of spin caloritronic devices. Here, we construct a spin-Seebeck device by inserting a strongly correlated quantum dot (QD) between the metal lead and magnetic insulator. Using the slave-particle approach and non-crossing approximation, we find that the spin-Seebeck effect increases significantly when the energy level of the QD locates near the Fermi level of the metal lead due to the enhancement of spin...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1612.05595
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3.0
Jun 30, 2018
06/18
by
J. Munevar; M. Cabrera-Baez; M. Alzamora; J. Larrea; E. M. Bittar; E. Baggio-Saitovitch; F. J. Litterst; R. A. Ribeiro; M. A. Avila; E. Morenzoni
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Temperature dependent magnetization, muon spin rotation and $^{57}$Fe M\"ossbauer spectroscopy experiments performed on crystals of intermetallic FeGa$_{3-y}$Ge$_{y}$ ($y=0.11,0.14,0.17,0.22,0.27$, $0.29,0.32$) are reported. Whereas at $y=0.11$ even a sensitive magnetic microprobe such as $\mu$SR does not detect magnetism, all other samples display weak ferromagnetism with a magnetic moment of up to 0.22 $\mu_B$ per Fe atom. As a function of doping and of temperature a crossover from short...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1701.01618
