Related papers: Mass Enhancement in an Intermediate-Valent Regime …
Many heavy fermion materials are known to crossover from the Kondo lattice regime to the mixed-valent regime or vice-versa as a function of pressure or doping. We study this crossover theoretically by employing the periodic Anderson model…
We study an extended periodic Anderson model with the Coulomb interaction Ucf between conduction and f electrons by the Gutzwiller method. The crossovers between the Kondo, intermediate-valence, and almost empty f-electron regimes become…
Emphasis is given on the observation of a convergence to a critical value of the effective mass of a heavy fermion compound by tuning it through a quantum instability either by applying pressure or magnetic field from an antiferromagnetic…
A strong electron-phonon interaction in a metal increases the electron density of states in the vicinity of the Fermi energy dramatically. This phenomenon is called electron-phonon mass enhancement. In this paper the question is…
We have investigated heavy-fermion behavior of the transition-metal oxides ACu3Ru4O12 (A = Na, Ca, La, and their mixtures). It has been known that CaCu3Ru4O12 exhibits Kondo-like behavior attributable to Cu2+ 3d electrons, similar to that…
Ground state properties of a Kondo lattice model with random configuration of $f$ electrons are investigated with a variational Monte Carlo method. We show that the crossover from a dilute-Kondo system to a heavy-fermion system occurs when…
Intermetallic compounds containing $f$-electron elements have been prototypical materials for investigating strong electron correlations and quantum criticality (QC). Their heavy fermion ground state evoked by the magnetic $f$-electrons is…
For describing the first-order isostructural valence phase transition in mixed valence compounds we develop a new approach based on the lattice Anderson model. We take into account the Coulomb interaction between localized f and conduction…
An interplay of the Kondo scattering and exciton effects (d-f Coulomb interaction) in the intermediate valence systems and Kondo lattices is demonstrated to lead to an essential change of the scaling behavior in comparison with the standard…
Recent observation of a mass enhancement in high magnetic fields in nearly optimally doped cuprates poses several puzzles. For the suggested nodal electron pocket induced by bidirectional charge order in high field, we propose that the mass…
Using dynamical-mean-field theory, we investigate the electronic properties of quantum wells consisting of a $t^1_{2g}$-electron system with strong correlations. The special focus is on the subband structure of such quantum wells. The…
A brief review on major advances in heavy fermion physics is presented including the Ce metal phase diagram, the huge effective mass detected in CeAl3, and the successive discoveries of unconventional superconductivity in CeCu2Si2 and three…
We investigate the metamagnetism in the periodic Anderson model with the $\bm{k}$-dependent $c-f$ mixing by using the dynamical mean-field theory combined with the exact diagonalization method. It is found that both effects of the…
Composite fermions (CFs), exotic quasi-particles formed by pairing an electron and an even number of magnetic flux quanta emerge at high magnetic fields in an interacting electron system, and can explain phenomena such as the fractional…
Ubiquity of unconventional phenomena observed in a series of heavy fermion metals is discussed on the basis of an idea of critical valence fluctuations. After surveying experimental aspects of these unconventional behaviors in prototypical…
We study the dynamics of a quantum critical boson coupled to a Fermi surface in intermediate energy regimes where the Landau damping of the boson can be parametrically controlled, either via large Fermi velocity or by large N techniques. We…
We propose a model intended to qualitatively capture the electron-electron interaction physics of two-dimensional electron gases formed near transition-metal oxide heterojunctions containing $t_{2g}$ electrons with a density much smaller…
The interface between a heavy electron coherent metallic phase and an incoherent normal metal phase is discussed. The Fermi momentum mismatch between the two phases causes the carriers to scatter at the interface. The interface conductance…
We show that the quasiparticle effective mass $M^*$ diverges as a function of the system's density $x$, $M^*\propto 1/(x-x_{FC})$, when a system approaches the critical point $x_{FC}$ at which the fermion condensation quantum phase…
We report measurements of the physical properties and electronic structure of the hexagonal compounds Yb2Ni12Pn7 (Pn = P, As) by measuring the electrical resistivity, magnetization, specific heat and partial fluorescence yield x-ray…