16
16
Jun 27, 2018
06/18
by
A. -M. Uimonen; G. Stefanucci; Y. Pavlyukh; R. van Leeuwen
texts
eye 16
favorite 0
comment 0
In a recent paper [Phys. Rev. B 90, 115134 (2014)] we put forward a diagrammatic expansion for the self-energy which guarantees the positivity of the spectral function. In this work we extend the theory to the density response function. We write the generic diagram for the density-response spectrum as the sum of partitions. In a partition the original diagram is evaluated using time-ordered Green's functions (GF) on the left-half of the diagram, antitime-ordered GF on the right-half of the...
Topics: Other Condensed Matter, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1503.02158
4
4.0
Jun 28, 2018
06/18
by
A. -M. Visuri; T. Giamarchi; P. Törmä
texts
eye 4
favorite 0
comment 0
We study analytically and with the numerical time-evolving block decimation method the dynamics of an impurity in a bath of spinless fermions with nearest-neighbor interactions in a one-dimensional lattice. The bath is in a Mott insulator state with alternating sites occupied and the impurity interacts with the bath by repulsive on-site interactions. We find that when the magnitudes of the on-site and nearest-neighbor interactions are close to each other, the system shows excitations of two...
Topics: Quantum Gases, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1511.04276
6
6.0
Jun 29, 2018
06/18
by
A. A. Aczel; A. M. Cook; T. J. Williams; S. Calder; A. D. Christianson; G. -X. Cao; D. Mandrus; Y. B. Kim; A. Paramekanti
texts
eye 6
favorite 0
comment 0
We have performed inelastic neutron scattering (INS) experiments to investigate the magnetic excitations in the weakly distorted face-centered-cubic (fcc) iridate double perovskites La$_2$ZnIrO$_6$ and La$_2$MgIrO$_6$, which are characterized by A-type antiferromagnetic ground states. The powder inelastic neutron scattering data on these geometrically frustrated $j_{\rm eff}=1/2$ Mott insulators provide clear evidence for gapped spin wave excitations with very weak dispersion. The INS results...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1604.08431
6
6.0
Jun 30, 2018
06/18
by
A. A. Aczel; L. Li; V. O. Garlea; J. -Q. Yan; F. Weickert; M. Jaime; B. Maiorov; R. Movshovich; L. Civale; V. Keppens; D. Mandrus
texts
eye 6
favorite 0
comment 0
The AR$_2$O$_4$ family (R = rare earth) have recently been attracting interest as a new series of frustrated magnets, with the magnetic R atoms forming zigzag chains running along the $c$-axis. We have investigated polycrystalline BaNd$_2$O$_4$ with a combination of magnetization, heat capacity, and neutron powder diffraction (NPD) measurements. Magnetic Bragg peaks are observed below $T_N$ $=$ 1.7 K, and they can be indexed with a propagation vector of $\vec{k}$ $=$ (0 1/2 1/2). The signal...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1407.4098
15
15
Jun 26, 2018
06/18
by
A. A. Aczel; L. Li; V. O. Garlea; J. -Q. Yan; F. Weickert; V. S. Vapf; R. Movshovich; M. Jaime; P. J. Baker; V. Keppens; D. Mandrus
texts
eye 15
favorite 0
comment 0
We have investigated polycrystalline samples of the zigzag chain system BaTb$_2$O$_4$ with a combination of magnetic susceptibility, heat capacity, neutron powder diffraction, and muon spin relaxation measurements. Despite the onset of Tb$^{3+}$ short-range antiferromagnetic correlations at $|\theta_{CW}|$ $=$ 18.5 K and a very large effective moment, our combined measurements indicate that BaTb$_2$O$_4$ remains paramagnetic down to 0.095 K. The magnetic properties of this material show...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1502.05668
6
6.0
Jun 30, 2018
06/18
by
A. A. Aczel; P. J. Baker; D. E. Bugaris; J. Yeon; H. -C. zur Loye; T. Guidi; D. T. Adroja
texts
eye 6
favorite 0
comment 0
We find evidence for long-range and short-range ($\zeta$ $=$ 70 \AA~at 4 K) incommensurate magnetic order on the quasi-face-centered-cubic (FCC) lattices of the monoclinic double perovskites La$_2$NaRuO$_6$ and La$_2$NaOsO$_6$ respectively. Incommensurate magnetic order on the FCC lattice has not been predicted by mean field theory, but may arise via a delicate balance of inequivalent nearest neighbour and next nearest neighbour exchange interactions. In the Ru system with long-range order,...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1401.1496
4
4.0
Jun 29, 2018
06/18
by
A. A. Aczel; Z. Zhao; S. Calder; D. T. Adroja; P. J. Baker; J. -Q. Yan
texts
eye 4
favorite 0
comment 0
We have performed magnetic susceptibility, heat capacity, neutron powder diffraction, and muon spin relaxation experiments to investigate the magnetic ground states of the 5$d^2$ double perovskites Sr$_2$YReO$_6$ and Sr$_2$InReO$_6$. We find that Sr$_2$YReO$_6$ is a spin glass, while Sr$_2$InReO$_6$ hosts a non-magnetic singlet state. By making detailed comparisons with other 5$d^2$ double perovskites, we argue that a delicate interplay between spin-orbit coupling, non-cubic crystal fields, and...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1602.02978
4
4.0
Jun 30, 2018
06/18
by
A. A. Aligia
texts
eye 4
favorite 0
comment 0
Using non-equilibrium renormalized perturbation theory to second order in the renormalized Coulomb repulsion, we calculate the lesser $\Sigma^ $ self-energies of the impurity Anderson model, which describes the current through a quantum dot, in the general asymmetric case. While in general a numerical integration is required to evaluate the perturbative result, we derive an analytical approximation for small frequency $\omega$, bias voltage $V$ and temperature $T$ which is exact to total second...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1403.3452
12
12
Jun 27, 2018
06/18
by
A. A. Aligia; P. Roura Bas; S. Florens
texts
eye 12
favorite 0
comment 0
We investigate theorerically the non-equilibrium transport through a molecular quantum dot as a function of gate and bias voltage, taking into account the typical situation in molecular electronics. In this respect, our study includes asymmetries both in the capacitances and tunneling rates to the source and drain electrodes, as well as an infinitely large charging energy on the molecule. Our calculations are based on the out-of-equilibrium Non-Crossing-Approximation (NCA), which is a reliable...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1505.03722
3
3.0
Jun 30, 2018
06/18
by
A. A. Katanin
texts
eye 3
favorite 0
comment 0
We consider formulations of the functional renormaliztion-group flow for correlated electronic systems, having the dynamical mean-field theory as a starting point. We classify the corresponding renormalization-group schemes into those neglecting the one-particle irreducible (with respect to the local Green functions) six-point vertices and neglecting one-particle reducible six-point vertices. The former class is represented by the recently introduced DMF$^{2}$RG approach [Phys. Rev. Lett. 112,...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1412.7266
21
21
Jun 28, 2018
06/18
by
A. A. Katanin
texts
eye 21
favorite 0
comment 0
In this paper we consider the possibility of chiral (charge or spin density wave) symmetry breaking in graphene due to long-range Coulomb interaction by comparing the results of the Bethe-Salpeter and functional renormalization-group approaches. The former approach performs summation of ladder diagrams in the particle-hole channel, and reproduces the results of the Schwinger-Dyson approach for the critical interaction strength of the quantum phase transition. The renormalization-group approach...
Topics: High Energy Physics - Theory, Strongly Correlated Electrons, Condensed Matter, Materials Science
Source: http://arxiv.org/abs/1508.07224
6
6.0
Jun 29, 2018
06/18
by
A. A. Katanin
texts
eye 6
favorite 0
comment 0
We suggest a new approach for treatment of local and non-local interactions in correlated electronic systems, which is based on the combination of the (extended) dynamical mean-field theory ((E)DMFT) and the two-particle irreducible functional renormaliztion-group (2PI-fRG) method. The considering approach uses self-energy and the two-particle irreducible vertices, obtained from (E)DMFT, as an input of 2PI-fRG approach. Using 2PI vertices may improve the applicability of various truncations and...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1604.01702
4
4.0
Jun 29, 2018
06/18
by
A. A. Katanin; A. S. Belozerov; V. I. Anisimov
texts
eye 4
favorite 0
comment 0
We consider nonlocal correlations in iron in the vicinity of the $\alpha$-$\gamma$ phase transition within the spin-rotationally-invariant dynamical mean-field theory (DMFT) approach, combined with the recently proposed spin-fermion model of iron. The obtained nonlocal corrections to DMFT yield a decrease of the Curie temperature of the $\alpha$ phase, leading to an agreement with its experimental value. We show that the corresponding nonlocal corrections to the energy of the $\alpha$ phase are...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1605.04589
8
8.0
Jun 29, 2018
06/18
by
A. A. Khajetoorians; M. Valentyuk; M. Steinbrecher; T. Schlenk; A. Shick; J. Kolorenc; A. I. Lichtenstein; T. O. Wehling; R. Wiesendanger; J. Wiebe
texts
eye 8
favorite 0
comment 0
The recently proposed theoretical concept of a Hund's metal is regarded as a key to explain the exotic magnetic and electronic behavior occuring in the strongly correlated electron systems of multiorbital metallic materials. However, a tuning of the abundance of parameters, that determine these systems, is experimentally challenging. Here, we investigate the smallest possible realization of a Hund's metal, a Hund's impurity, realized by a single magnetic impurity strongly hybridized to a...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1604.03854
11
11
Jun 26, 2018
06/18
by
A. A. Kordyuk
texts
eye 11
favorite 0
comment 0
A term first coined by Mott back in 1968 a `pseudogap' is the depletion of the electronic density of states at the Fermi level, and pseudogaps have been observed in many systems. However, since the discovery of the high temperature superconductors (HTSC) in 1986, the central role attributed to the pseudogap in these systems has meant that by many researchers now associate the term pseudogap exclusively with the HTSC phenomenon. Recently, the problem has got a lot of new attention with the...
Topics: Superconductivity, Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.04154
3
3.0
Jun 30, 2018
06/18
by
A. A. Lopes; R. G. Dias
texts
eye 3
favorite 0
comment 0
We present a new method for the determination of the two-terminal differential conductance through an interacting cluster, where one maps the interacting cluster into a non-interacting cluster of $M$ independent sites (where $M$ is the number of cluster states with one particle more or less than the ground state of the cluster), with different onsite energy and connected to the leads with renormalized hoppings constants. The onsite energies are determined from the one-particle (one-hole)...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1407.5922
5
5.0
Jun 30, 2018
06/18
by
A. A. Nikolaev; M. V. Ulybyshev
texts
eye 5
favorite 0
comment 0
Tight-binding model of the AA-stacked bilayer graphene with screened electron-electron interactions has been studied using the Hybrid Monte Carlo simulations on the original double-layer hexagonal lattice. Instantaneous screened Coulomb potential is taken into account using Hubbard-Stratonovich transformation. G-type antiferromagnetic ordering has been studied and the phase transition with spontaneous generation of the mass gap has been observed. Dependence of the antiferromagnetic condensate...
Topics: High Energy Physics - Lattice, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1412.1359
9
9.0
Jun 29, 2018
06/18
by
A. A. Novoselov; O. V. Pavlovsky
texts
eye 9
favorite 0
comment 0
Due to its unique structure, graphene provides a condensed-matter model of particle physics phenomena. One is the critical charge which is highly interested. The investigation of critical charge in gapped graphene is performed within single particle approach by means of Dirac equation integration. The screened Coulomb interaction between charged defect and graphene electron excitations is investigated. Two kinds of mass gap generation and various values of substrate dielectric permittivities...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.08479
17
17
Jun 26, 2018
06/18
by
A. A. Ovchinnikov
texts
eye 17
favorite 0
comment 0
We obtain the Baxter Q-operators in the $U_q(\hat{sl}_2)$ invariant integrable models as a special limits of the quantum transfer matrices corresponding to different spins in the auxiliary space both from the functional relations and from the explicit calculations. We derive the Baxter equation from the well known fusion relations for the transfer matrices. Our method is valid for an arbitrary integrable model corresponding to the quantum group $U_q(\hat{sl}_2)$ for example for the XXZ- spin...
Topics: Mathematical Physics, Mathematics, High Energy Physics - Theory, Condensed Matter, Strongly...
Source: http://arxiv.org/abs/1501.03663
6
6.0
Jun 28, 2018
06/18
by
A. A. Ovchinnikov
texts
eye 6
favorite 0
comment 0
We calculate the threshold singularities in one-dimensional models using the universal low-energy formfactors obtained in the framework of the non-linear Luttinger liquid model. We find the reason why the simplified picture of the impurity moving in the Luttinger liquid leads to the correct results. We obtain the prefactors of the singularities including their $k$- dependence at small $k
Topics: High Energy Physics - Theory, Mathematics, Strongly Correlated Electrons, Mathematical Physics,...
Source: http://arxiv.org/abs/1511.07684
3
3.0
Jun 29, 2018
06/18
by
A. A. Shashkin; S. V. Kravchenko
texts
eye 3
favorite 0
comment 0
Experimental results on the metal-insulator transition and related phenomena in strongly interacting two-dimensional electron systems are discussed. Special attention is given to recent results for the strongly enhanced spin susceptibility, effective mass, and thermopower in low-disordered silicon MOSFETs.
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.05645
3
3.0
Jun 30, 2018
06/18
by
A. A. Shashkin; V. T. Dolgopolov; J. W. Clark; V. R. Shaginyan; M. V. Zverev; V. A. Khodel
texts
eye 3
favorite 0
comment 0
We show that the merging of the spin- and valley-split Landau levels at the chemical potential is an intrinsic property of a strongly-interacting two-dimensional electron system in silicon. Evidence for the level merging is given by available experimental data.
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1404.7465
7
7.0
Jun 29, 2018
06/18
by
A. A. Sinchenko; P. Lejay; O. Leynaud; P. Monceau
texts
eye 7
favorite 0
comment 0
We report a strong difference in the sliding properties of the bidirectional charge density wave (CDW) in the two-dimensional rare earth tritelluride ErTe$_3$ which occurs below $T_{CDW1}=265$ K with a wave vector along $c$-axis and below $T_{CDW2}=165$ K with a wave vector along $a$-axis; the excess current carried by the motion of the CDW is 10 times less for the lower CDW compared with the value of the upper one. We tentatively explain this result by a stronger pinning of the lower...
Topics: Mesoscale and Nanoscale Physics, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1606.06527
5
5.0
Jun 30, 2018
06/18
by
A. A. Taskin; Henry F. Legg; Fan Yang; Satoshi Sasaki; Yasushi Kanai; Kazuhiko Matsumoto; Achim Rosch; Yoichi Ando
texts
eye 5
favorite 0
comment 0
A prominent feature of topological insulators (TIs) is the surface states comprising of spin-nondegenerate massless Dirac fermions. Recent technical advances have made it possible to address the surface transport properties of TI thin films while tuning the Fermi levels of both top and bottom surfaces across the Dirac point by electrostatic gating. This opened the window for studying the spin-nondegenerate Dirac physics peculiar to TIs. Here we report our discovery of a novel planar Hall effect...
Topics: Strongly Correlated Electrons, Materials Science, Mesoscale and Nanoscale Physics, Condensed Matter
Source: http://arxiv.org/abs/1703.03406
3
3.0
Jun 30, 2018
06/18
by
A. A. Tsirlin; M. G. Rabie; A. Efimenko; Z. Hu; R. Saez-Puche; L. H. Tjeng
texts
eye 3
favorite 0
comment 0
We have investigated the electronic structure of the high oxidation state material YCrO$_4$ within the framework of the Zaanen-Sawatzky-Allen phase diagram. While Cr$^{4+}$-based compounds like SrCrO$_3$/CaCrO$_3$ and CrO$_2$ can be classified as small-gap or metallic negative-charge-transfer systems, we find using photoelectron spectroscopy that YCrO$_4$ is a robust insulator despite the fact that its Cr ions have an even higher formal valence state of 5+. We reveal using band structure...
Topics: Strongly Correlated Electrons, Materials Science, Condensed Matter
Source: http://arxiv.org/abs/1408.2396
4
4.0
Jun 29, 2018
06/18
by
A. A. Vladimirov; D. Ihle; N. M. Plakida
texts
eye 4
favorite 0
comment 0
We consider the quasi-two-dimensional pseudo-spin-1/2 Kitaev - Heisenberg model proposed for A2IrO3 (A=Li, Na) compounds. The spin-wave excitation spectrum, the sublattice magnetization, and the transition temperatures are calculated in the random phase approximation (RPA) for four different ordered phases, observed in the parameter space of the model: antiferomagnetic, stripe, ferromagnetic, and zigzag phases. The N\'{e}el temperature and temperature dependence of the sublattice magnetization...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1602.01961
6
6.0
Jun 30, 2018
06/18
by
A. A. Vladimirov; D. Ihle; N. M. Plakida
texts
eye 6
favorite 0
comment 0
We present a spin-rotation-invariant Green-function theory for the dynamic spin susceptibility in the spin-1/2 antiferromagnetic Heisenberg model on a stacked honeycomb lattice. Employing a generalized mean-field approximation for arbitrary temperatures, the thermodynamic quantities (two-spin correlation functions, internal energy, magnetic susceptibility, staggered magnetization, N'eel temperature, correlation length) and the spin-excitation spectrum are calculated by solving a coupled system...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1703.08391
6
6.0
Jun 30, 2018
06/18
by
A. A. Vladimirov; D. Ihle; N. M. Plakida
texts
eye 6
favorite 0
comment 0
The spin-wave excitation spectrum, the magnetization, and the N\'{e}el temperature for the quasi-two-dimensional spin-1/2 antiferromagnetic Heisenberg model with compass-model interaction in the plane proposed for iridates are calculated in the random phase approximation. The spin-wave spectrum agrees well with data of Lanczos diagonalization. We find that the Neel temperature is enhanced by the compass-model interaction and is close to the experimental value for Ba2IrO4.
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1411.3920
16
16
Jun 27, 2018
06/18
by
A. A. Vladimirov; D. Ihle; N. M. Plakida
texts
eye 16
favorite 0
comment 0
A Green-function theory for the dynamic spin susceptibility in the square-lattice spin-1/2 antiferromagnetic compass-Heisenberg model employing a generalized mean-field approximation is presented. The theory describes magnetic long-range order (LRO) and short-range order (SRO) at arbitrary temperatures. The magnetization, N'eel temperature T_N, specific heat, and uniform static spin susceptibility $\chi$ are calculated self-consistently. As the main result, we obtain LRO at finite temperatures...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1506.01834
5
5.0
Jun 30, 2018
06/18
by
A. A. Zvyagin
texts
eye 5
favorite 0
comment 0
During recent years the interest to dynamics of quantum systems has grown considerably. Quantum many body systems out of equilibrium often manifest behavior, different from the one predicted by standard statistical mechanics and thermodynamics in equilibrium. Since the dynamics of a many body quantum system typically involve many excited eigenstates, with a non-thermal distribution, the time evolution of such a system provides an unique way for investigation of non-equilibrium quantum...
Topics: Strongly Correlated Electrons, Statistical Mechanics, Condensed Matter
Source: http://arxiv.org/abs/1701.08851
4
4.0
Jun 30, 2018
06/18
by
A. A. Zvyagin; H. Johannesson
texts
eye 4
favorite 0
comment 0
We introduce an integrable model of spin-polarized interacting electrons subject to a spin-conserving spin-orbit interaction. Using Bethe Ansatz and conformal field theory we calculate the exact large-time single-electron and density correlations and find that while the spin-orbit interaction enhances the single-electron Green's function, the density correlations get suppressed. Adding a localized impurity and coupling it to the electrons so that integrability is preserved, the dynamic...
Topics: Nonlinear Sciences, Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Exactly...
Source: http://arxiv.org/abs/1403.6091
62
62
Jun 30, 2018
06/18
by
A. Alexandradinata; B. Andrei Bernevig
texts
eye 62
favorite 0
comment 0
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
46
46
Jun 30, 2018
06/18
by
A. Alexandradinata; Chen Fang; Matthew J. Gilbert; B. Andrei Bernevig
texts
eye 46
favorite 0
comment 0
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
16
16
Jun 27, 2018
06/18
by
A. Alexandradinata; N. Regnault; Chen Fang; Matthew J. Gilbert; B. Andrei Bernevig
texts
eye 16
favorite 0
comment 0
Parafermions are the simplest generalizations of Majorana fermions that realize topological order. We propose a less restrictive notion of topological order in 1D open chains, which generalizes the seminal work by Fendley [J. Stat. Mech., P11020 (2012)]. The first essential property is that the groundstates are mutually indistinguishable by local, symmetric probes, and the second is a generalized notion of zero edge modes which cyclically permute the groundstates. These two properties are shown...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1506.03455
3
3.0
Jun 29, 2018
06/18
by
A. Allerdt; A. E. Feiguin; S. Das Sarma
texts
eye 3
favorite 0
comment 0
The cooperative behavior of quantum impurities on 2D materials, such as graphene and bilayer graphene, is characterized by a non-trivial competition between screening (Kondo effect), and Ruderman-Kittel-Kasuya-Yosida (RKKY) magnetism. In addition, due to the small density of states at the Fermi level, impurities may not couple to the conduction electrons at all, behaving as free moments. Employing a recently developed {\em{exact}} numerical method to study multi-impurity lattice systems, we...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1604.06109
8
8.0
Jun 30, 2018
06/18
by
A. Altland; B. Beri; R. Egger; A. M. Tsvelik
texts
eye 8
favorite 0
comment 0
Conduction electrons coupled to a mesoscopic superconducting island hosting Majorana bound states have been shown to display a topological Kondo effect with robust non-Fermi liquid correlations. With $M$ bound states coupled to $M$ leads, this is an SO($M$) Kondo problem, with the asymptotic high and low energy theories known from bosonization and conformal field theory studies. Here we complement these approaches by analyzing the Bethe ansatz equations describing the exact solution of these...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1403.0113
3
3.0
Jun 30, 2018
06/18
by
A. Amaricci; J. C. Budich; M. Capone; B. Trauzettel; G. Sangiovanni
texts
eye 3
favorite 0
comment 0
Topological quantum phase transitions are characterised by changes in global topological invariants. These invariants classify many body systems beyond the conventional paradigm of local order parameters describing spontaneous symmetry breaking. For non-interacting electrons, it is well understood that such transitions are continuous and always accompanied by a gap-closing in the energy spectrum, given that the symmetries protecting the topological phase are maintained. Here, we demonstrate...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1411.7390
6
6.0
Jun 29, 2018
06/18
by
A. Amaricci; J. C. Budich; M. Capone; B. Trauzettel; G. Sangiovanni
texts
eye 6
favorite 0
comment 0
We investigate the role of short-ranged electron-electron interactions in a paradigmatic model of three dimensional topological insulators, using dynamical mean-field theory and focusing on non magnetically ordered solutions. The non-interacting band-structure is controlled by a mass term M, whose value discriminates between three different insulating phases, a trivial band insulator and two distinct topologically non-trivial phases. We characterize the evolution of the transitions between the...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1603.04263
6
6.0
Jun 30, 2018
06/18
by
A. Amaricci; M. Capone
texts
eye 6
favorite 0
comment 0
Using dynamical mean-field theory (DMFT) we study a simplified model for heterostructures involving superconductors. The system is driven out-of-equilibrium by a voltage bias, imposed as an imbalance of chemical potential at the interface. We solve the self-consistent DMFT equations using iterative second-order perturbation theory in the Nambu-Keldysh formalism. We show that the superconducting state is destabilized by voltage biases of the order of the energy gap. We demonstrate that the...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1411.2347
7
7.0
Jun 30, 2018
06/18
by
A. Amato; P. Dalmas de Réotier; D. Andreica; A. Yaouanc; A. Suter; G. Lapertot; I. M. Pop; E. Morenzoni; P. Bonfà; F. Bernardini; R. De Renzi
texts
eye 7
favorite 0
comment 0
Transverse-field muon-spin rotation ($\mu$SR) experiments were performed on a single crystal sample of the non-centrosymmetric system MnSi. The observed angular dependence of the muon precession frequencies matches perfectly the one of the Mn-dipolar fields acting on the muons stopping at a 4a position of the crystallographic structure. The data provide a precise determination of the magnetic dipolar tensor. In addition, we have calculated the shape of the field distribution expected below the...
Topics: Other Condensed Matter, Strongly Correlated Electrons, Materials Science, Condensed Matter
Source: http://arxiv.org/abs/1405.0140
7
7.0
Jun 30, 2018
06/18
by
A. Andreanov; P. A. McClarty
texts
eye 7
favorite 0
comment 0
XY pyrochlore antiferromagnets are well-known to exhibit order-by-disorder through both quantum and thermal selection. In this paper we consider the effect of substituting non-magnetic ions onto the magnetic sites in a pyrochlore XY model with generally anisotropic exchange tuned by a single parameter $J^{\pm\pm}/J^\pm$. The physics is controlled by two points in this space of parameters $J^{\pm\pm}/J^\pm=\pm 2$ at which there are line modes in the ground state and hence an $O(L^2)$ ground...
Topics: Strongly Correlated Electrons, Disordered Systems and Neural Networks, Condensed Matter
Source: http://arxiv.org/abs/1408.7119
3
3.0
Jun 30, 2018
06/18
by
A. B. Odobescu; A. A. Maizlakh; S. V. Zaitsev-Zotov
texts
eye 3
favorite 0
comment 0
Electronic properties of the Si(111)-$7\times 7$ surface are studied using four- and two-probe conductivity measurements and tunneling spectroscopy. We demonstrate that the temperature dependence of the surface conductivity corresponds to the Efros-Shklovskii law at least in $10-100$~K temperature range. The energy gap at the Fermi level observed in tunneling spectroscopy measurements at $T\geq 5$~K vanishes by thermal fluctuations at $T\approx 30$~K, without any sign of the metal-insulator...
Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Materials Science, Condensed Matter
Source: http://arxiv.org/abs/1411.5590
10
10.0
Jun 28, 2018
06/18
by
A. B. Shick; L. Havela; A. I. Lichtenstein; M. I. Katsnelson
texts
eye 10
favorite 0
comment 0
We address the long-standing mystery of the nonmagnetic insulating state of the intermediate valence compound SmB$_6$. Within a combination of the local density approximation (LDA) and an exact diagonalization (ED) of an effective discrete Anderson impurity model, the intermediate valence ground state with the $f$-shell occupation $\langle n_{4f} \rangle=5.6$ is found for the Sm atom in SmB$_6$. This ground state is a singlet, and the first excited triplet state $\sim 3$ meV higher in the...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1510.06968
4
4.0
Jun 30, 2018
06/18
by
A. B. Sushkov; Ch. Kant; M. Schiebl; A. M. Shuvaev; Anna Pimenov; Andrei Pimenov; B. Lorenz; S. Park; S-W. Cheong; Maxim Mostovoy; H. D. Drew
texts
eye 4
favorite 0
comment 0
The origin of the colossal magnetodielectric effect in DyMn2O5 [1] has been an outstanding question in multiferroics. Here, we report the activation of the electric dipole mode at 4-5 cm-1 in an applied magnetic field which fully accounts for the CMD effect. We examine two alternative explanations of this mode: an electromagnon and transitions between f-electron levels of Dy3+ ions. The experimental and theoretical evidence supports the electromagnon origin of the CMD effect.
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1403.3717
5
5.0
Jun 30, 2018
06/18
by
A. B. Ward; R. T. Clay; S. Mazumdar
texts
eye 5
favorite 0
comment 0
Yoshimi et al. [arXiv:1110.3573] have attempted to explain the pressure(P)-dependent behavior of Fabre salts which exhibit charge order (CO), antiferromagnetic (AFM), and spin-Peierls (SP) phases. Experiments find two AFM phases, AFM1 at large P and AFM2 at small P. Yoshimi et al. suggest that there also exist two distinct zero-temperature SP phases, SP1 and SP2. Here we point out that the occurrence of two distinct SP phases contradicts experiments, and is found because of unrealistic model...
Topics: Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1403.0120
3
3.0
Jun 29, 2018
06/18
by
A. Bagrov; N. Kaplis; A. Krikun; K. Schalm; J. Zaanen
texts
eye 3
favorite 0
comment 0
It is presently unknown how strong lattice potentials influence the fermion spectral function of the holographic strange metals predicted by the AdS/CFT correspondence. This embodies a crucial test for the application of holography to condensed matter experiments. We show that for one particular momentum direction this spectrum can be computed for arbitrary strength of the effective translational symmetry breaking potential of the so-called Bianchi-VII geometry employing ordinary differential...
Topics: High Energy Physics - Theory, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1608.03738
4
4.0
Jun 29, 2018
06/18
by
A. Banerjee; J. Sannigrahi; S. Bhowal; I. Dasgupta; S. Majumdar; H. C. Walker; A. Bhattacharyya; D. T. Adroja
texts
eye 4
favorite 0
comment 0
The pyrovanadate alpha-Cu2V2O7 belongs to the orthorhombic (Fdd2) class of crystals with noncentrosymmetric crystal structure. Recently, the compound has been identified to be a magnetic multiferroic with a substantial electric polarization below the magnetic transition temperature TC = 35 K. Here we report the results of our inelastic neutron scattering (INS) studies on a polycrystalline sample of alpha-Cu2V2O7. Our INS data clearly show the existence of dispersive spin wave excitations below...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1610.03969
9
9.0
Jun 29, 2018
06/18
by
A. Bauer; A. Chacon; M. Wagner; M. Halder. R. Georgii; A. Rosch; C. Pfleiderer; M. Garst
texts
eye 9
favorite 0
comment 0
We report a study of the reorientation of the helimagnetic order in the archetypal cubic chiral magnet MnSi as a function of magnetic field direction. The reorientation process as inferred from small-angle neutron scattering, the magnetization, and the ac susceptibility is in excellent agreement with an effective mean-field theory taking into account the precise symmetries of the crystallographic space group. Depending on the field and temperature history and the direction of the field with...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.06835
15
15
Jun 27, 2018
06/18
by
A. Bauer; F. Dorfner; F. Heidrich-Meisner
texts
eye 15
favorite 0
comment 0
Motivated by recent experiments with ultra-cold quantum gases in optical lattices we study the decay of the staggered moment in the one-dimensional Fermi-Hubbard model starting from a perfect Neel state using exact diagonalization and the iTEBD method. This extends previous work in which the same problem has been addressed for pure spin Hamiltonians. As a main result, we show that the relaxation dynamics of the double occupancy and of the staggered moment are different. The former is controlled...
Topics: Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1503.02010
9
9.0
Jun 29, 2018
06/18
by
A. Bauer; G. Benka; A. Regnat; C. Franz; C. Pfleiderer
texts
eye 9
favorite 0
comment 0
We report the development of a versatile material preparation chain for intermetallic compounds that focuses on the realization of a high-purity growth environment. The preparation chain comprises of an argon glovebox, an inductively heated horizontal cold boat furnace, an arc melting furnace, an inductively heated rod casting furnace, an optically heated floating-zone furnace, a resistively heated annealing furnace, and an inductively heated annealing furnace. The cold boat furnace and the arc...
Topics: Materials Science, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1611.03392
