相关论文: Theory of valence transitions in ytterbium-based c…
The exact solution of the spin one-half Falicov-Kimball model, with random hopping between the lattice sites, is used to explain the anomalous magnetic response of Yb-based valence-fluctuating intermetallic compounds. The anomalous behavior…
The exact solution of the multi-component Falicov-Kimball model in infinite-dimensions is presented and used to discuss a new fixed point of valence fluctuating intermetallics with Yb and Eu ions. In these compounds, temperature, external…
We present a simple, but very realistic, model for a description of pressure induced valence and metal-insulator transitions in mixed valence systems. It is based on the extended Falicov-Kimball model and the supposition that the key…
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…
The spin-one-half Falicov-Kimball model is solved exactly on an infinite-coordination-number Bethe lattice in the thermodynamic limit. This model is a paradigm for a charge-transfer metal-insulator transition where the occupancy of…
The ground-state phase diagram of the spin-one-half Falicov-Kimball model (FKM) is studied in the one dimension using small-cluster exact-diagonalization calculations. The resultant exact solutions are used to examine possibilities for…
Metal-insulator transitions are studied within a three-component Falicov-Kimball model which mimics a mixture of one-component and two-component fermionic particles with local repulsive interactions in optical lattices. Within the model the…
The extrapolation of small-cluster exact-diagonalization calculations is used to examine the influence of correlated hopping on valence and metal-insulator transitions in the one-dimensional Falicov-Kimball model. It is shown that the…
We present a dynamical mean field theory study of the valence transition ($f^{14} \to f^{13}$) in elemental, metallic Yb under pressure. Our calculations reproduce the observed valence transition as reflected in the volume dependence of the…
The exact solution for the thermodynamic and dynamic properties of the infinite-dimensional multi-component Falicov-Kimball model for arbitrary concentration of d- and f-electrons is presented. The emphasis is on a descriptive derivation of…
The roles of critical valence fluctuations of Ce and Yb are discussed as a key origin of several anomalies observed in Ce- and Yb-based heavy fermion systems. Recent development of the theory has revealed that a magnetic field is an…
YbInCu$_4$ undergoes a first order structural phase transition near $T_v$=40 K associated with an abrupt change of Yb valence state. We perform ultrafast pump-probe measurement on YbInCu$_4$ and find that the expected heavy fermion…
A diffraction experiment using a high energy x-ray was carried out on YbInCu4. Below the Yb valence transition temperature, the splitting of Bragg peaks was detected in higher-order reflections. No superlattice reflections accompanying the…
Recent discoveries of a new type of quantum criticality arising from Yb-valence fluctuations in Yb-based metal in periodic crystal and quasicrystal have opened a new class of quantum critical phenomena in correlated electron systems. To…
The extrapolation of small-cluster exact-diagonalization calculations is used to study the influence of doping on valence transitions in the spinless Falicov-Kimball model at nonzero temperatures. Two types of doping are examined, and…
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…
The exact solution of the spin-1/2 Falicov-Kimball model on an infinite-coordination Bethe lattice is analyzed in the regime of ``classical'' intermediate valence. We find (i) either phase separation or a direct metal-insulator transition…
The extrapolation of finite-cluster calculations is used to examine properties of the one-dimensional Falicov-Kimball model with correla It is shown that the correlated hopping strongly influences both the transitions and the conducting…
Metal-insulator transitions in a three-component Falicov-Kimball model are investigated within the Kotliar-Ruckenstein slave boson mean-field approach. The model describes a mixture of two interacting fermion atom species loaded into an…
Progress of theories and experiments of the quantum valence criticality is overviewed focusing on recent discoveries of direct evidence of quantum critical point of valence transitions in periodic crystal $\alpha$-YbAl$_{1-x}$Fe$_x$B$_4$ at…