Extended Hubbard model of superconductivity and charge-density-waves in the layered 2H transition metal dichalcogenides

[摘要] Based on an extended Hubbard model and a simplified version of the fluctuation exchange (FLEX) approximation, we explore the charge-density wave (CDW) and superconductivity in the layered transition metal dichalcogenides (TMDs). A quantitative analysis on a simplified model of the 2H-TaS2 is presented. It is demonstrated that the CDW may originate from a combined effect of the scattering between flat bands and an intrinsic property of the off-site Coulomb repulsions. Moreover, the effect of the off-site Coulomb repulsion on the competition of the CDW and superconductivity is elaborated.

[发布日期] 2006-12-01

[关键词] FLUCTUATING ELECTRON-SYSTEMS;CONSERVING APPROXIMATIONS;BAND-STRUCTURES