Valence Fluctuations in an Extended Periodic Anderson Model

Charge fluctuations in an extended periodic Anderson model

“…We observe a rapid decrease of n f against ð0Þ f in the presence of the repulsion U cf . This implies the enhancement of valence fluctuations due to U cf , which is consistent with previous studies [3][4][5][6]. We note that no indication of a definite jump in n f versus ð0Þ f is seen at least for U ¼ 6210 and U cf p4; parameters of larger values are necessary for occurrence of a (sudden) valence transition as was shown in Ref.…”

“…The valence fluctuations are also enhanced by increasing the repulsion U cf and raising the f-electron level as in the previous studies and the present DMFT study. As was observed in the previous study with the DMFT [5], susceptibilities take maxima at finite q. Indeed, as seen in Fig.…”

“…In the previous work [5], we found that the valence fluctuations are enhanced by U cf , using the DMFT combined with quantum Monte Carlo method. Recently, Watanabe et al studied the same model with large U in one dimension with the density matrix renormalization group method (DMRG) [6], and showed that the valence instability critical point appears at U cf larger than the conduction band width 2W .…”

From mixed valence to the Kondo lattice regime

“…Miyake and co-workers [47] have used a variety of methods including the slave-boson approximation, the density matrix renormalization group etc to investigate the one dimensional extended PAM (EPAM), which includes the d − f repulsion effects represented by U cf . The EPAM has been investigated within dynamical mean field theory by Sugibayashi and Hirashima [48]using quantum Monte-Carlo methods. Their focus has been to understand the interplay between U cf , valence fluctuations and superconductivity.…”