Evolution of a Large Fermi Surface in the Kondo Lattice

Otsuki, Junya; Kusunose, Hiroaki; Kuramoto, Yoshio

doi:10.1103/physrevlett.102.017202

Cited by 60 publications

(66 citation statements)

References 24 publications

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“…The first two models play an important role in the theory of heavy fermion materials (Coleman, 2007), and all four have been studied intensively within equilibrium DMFT (Meyer, Hewson, and Bulla, 2002;Werner and Millis, 2007;De Leo, Civelli, and Kotliar, 2008;Otsuki, Kusunose, and Kuramoto, 2009). The Falicov-Kimball model…”

Section: Models a Overviewmentioning

confidence: 99%

Nonequilibrium dynamical mean-field theory and its applications

et al. 2014

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The study of nonequilibrium phenomena in correlated lattice systems has developed into one of the most active and exciting branches of condensed matter physics. This research field provides rich new insights that could not be obtained from the study of equilibrium situations, and the theoretical understanding of the physics often requires the development of new concepts and methods. On the experimental side, ultrafast pump-probe spectroscopies enable studies of excitation and relaxation phenomena in correlated electron systems, while ultracold atoms in optical lattices provide a new way to control and measure the time evolution of interacting lattice systems with a vastly different characteristic time scale compared to electron systems. A theoretical description of these phenomena is challenging because, first, the quantum-mechanical time evolution of many-body systems out of equilibrium must be computed and second, strong-correlation effects which can be of a nonperturbative nature must be addressed. This review discusses the nonequilibrium extension of the dynamical mean field theory (DMFT), which treats quantum fluctuations in the time domain and works directly in the thermodynamic limit. The method reduces the complexity of the calculation via a mapping to a selfconsistent impurity problem, which becomes exact in infinite dimensions. Particular emphasis is placed on a detailed derivation of the formalism, and on a discussion of numerical techniques, which enable solutions of the effective nonequilibrium DMFT impurity problem. Insights gained into the properties of the infinite-dimensional Hubbard model under strong nonequilibrium conditions are summarized. These examples illustrate the current ability of the theoretical framework to reproduce and understand fundamental nonequilibrium phenomena, such as the dielectric breakdown of Mott insulators, photodoping, and collapse-and-revival oscillations in quenched systems. Furthermore, remarkable novel phenomena have been predicted by the nonequilibrium DMFT simulations of correlated lattice systems, including dynamical phase transitions and field-induced repulsion-to-attraction conversions.

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Section: Models a Overviewmentioning

confidence: 99%

Nonequilibrium dynamical mean-field theory and its applications

et al. 2014

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“…The results are also con- sistent with the theoretical picture developed for the heavy Fermion compounds. [121][122][123][124] In the paramagnetic ground state like that H < H m in CeRu 2 Si 2 , the term "itinerant" can be used without ambiguity from the observation of the "large Fermi surface" or the two terms "itinerant" and "large Fermi surface" can be used equivalently. However, even when the observed volume of the Fermi surface is the same as or close to the volume of the small Fermi surface, the term "localized" may not be appropriate to characterize the f electron state in some cases.…”

Section: Fermi Surface Properties Of Ceru 2 Si 2 Below and Above The mentioning

confidence: 99%

“…But it could be explained by the two Fermi edges corresponding to the small and large Fermi surfaces and the former one diminishes while the latter one grows with decreasing temperature as expected in the case of compounds. 124 We show a schematic illustration for the distribution of the electrons in the momentum space in Fig. 38.…”

Section: Appreciably This Observation Indicates That the Fermi Surfamentioning

confidence: 99%

Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu₂Si₂ and Its Alloys Probed by the dHvA Effect

2014

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This article describes the Fermi surface properties of CeRu 2 Si 2 and its alloy systems CeRu 2 (Si x Ge 1−x ) 2 and Ce x La 1−x Ru 2 Si 2 studied by the de Haas -van Alphen (dHvA) effect. We pay particular attention to how the Fermi surface properties and the f electron state change with magnetic properties, in particular how they change associated with metamagnetic transition and quantum phase transition. After summarizing the

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“…The gap in the electronic density of states (DOS) either opens gradually with decreasing temperature, as the pseudogap of high-temperature superconductors [1], or emerges at a continuous or first order phase transition [2][3][4]. In heavy fermion compounds [5] -systems in which f and conduction electrons strongly interact -a narrow hybridization gap is known to emerge gradually [6][7][8][9]. Generically, the Fermi energy is situated in one of the hybridized bands and a metallic heavy fermion ground state arises.…”

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confidence: 99%

Anisotropic optical conductivity of the putative Kondo insulator CeRu4Sn6

et al. 2013

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Kondo insulators and in particular their non-cubic representatives have remained poorly understood. Here we report on the development of an anisotropic energy pseudogap in the tetragonal compound CeRu4Sn6 employing optical reflectivity measurements in broad frequency and temperature ranges, and local density approximation plus dynamical mean field theory calculations. The calculations provide evidence for a Kondo insulator-like response within the a − a plane and a more metallic response along the c axis and qualitatively reproduce the experimental observations, helping to identify their origin.Correlated materials with gapped or pseudo-gapped ground states continue to be of great interest. The gap in the electronic density of states (DOS) either opens gradually with decreasing temperature, as the pseudogap of high-temperature superconductors [1], or emerges at a continuous or first order phase transition [2][3][4]. In heavy fermion compounds [5] -systems in which f and conduction electrons strongly interact -a narrow hybridization gap is known to emerge gradually [6][7][8][9]. Generically, the Fermi energy is situated in one of the hybridized bands and a metallic heavy fermion ground state arises. Only for special cases the Fermi energy lies within the gap and the ground state is Kondo insulating. Metallic heavy fermion systems have been intensively investigated over the past decades and are now, at least away from quantum criticality [10], well understood [11] within the framework of Landau Fermi liquid theory. Hence, a very few parameters, most notably the effective mass, allow us to describe thermodynamic and transport properties at the lowest temperatures. In comparison, the physics of Kondo insulators has proven to be much less tractable. This is at least in part due to the fact that the gapped ground state inhibits a characterization via the above properties. Many experimental efforts have therefore focussed on the determination of the gap width from temperature dependencies, which has frequently led to conflicting results, in particular for anisotropic Kondo insulators such as CeNiSn [12]. Here the strongly anisotropic transport and magnetic properties have been interpreted phenomenologically on the basis of a V-shaped DOS [13] or by invoking a hybridization gap with nodes [14][15][16] or extrinsic effects such as impurities, off stoichiometry or strain [17,18]. To advance the field it appears mandatory to model a number of carefully chosen materials ab initio, taking all essential ingredients into account.Here we investigate a new material, CeRu 4 Sn 6 , which due to its tetragonal crystal structure is simpler than the previously studied orthorhombic materials. In a combined experimental and theoretical effort we provide direct spectroscopic evidence for the development of an anisotropic pseudogap: While weak metallicity prevails in the optical conductivity along the c axis, insulatorlike behavior without a Drude peak is observed in the a − a plane. We trace this back to a correlated band structure whic...

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Evolution of a Large Fermi Surface in the Kondo Lattice

Cited by 60 publications

References 24 publications

Nonequilibrium dynamical mean-field theory and its applications

Nonequilibrium dynamical mean-field theory and its applications

Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu₂Si₂ and Its Alloys Probed by the dHvA Effect

Anisotropic optical conductivity of the putative Kondo insulator CeRu4Sn6

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Evolution of a Large Fermi Surface in the Kondo Lattice

Cited by 60 publications

References 24 publications

Nonequilibrium dynamical mean-field theory and its applications

Nonequilibrium dynamical mean-field theory and its applications

Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu2Si2 and Its Alloys Probed by the dHvA Effect

Anisotropic optical conductivity of the putative Kondo insulator CeRu4Sn6

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Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu₂Si₂ and Its Alloys Probed by the dHvA Effect