Spectral broadening due to long-range Coulomb interactions in the molecular metal TTF-TCNQ

Título del postprint: Coulomb parameters and photoemission for the molecular metal TTF-TCNQ
We employ density-functional theory to calculate realistic parameters for an extended Hubbard model of the molecular metal TTF-TCNQ. Considering both intra- and intermolecular screening in the crystal, we find significant longer-range Coulomb interactions along the molecular stacks, as well as inter-stack coupling. We show that the long-range Coulomb term of the extended Hubbard model leads to a broadening of the spectral density, likely resolving the problems with the interpretation of photoemission experiments using a simple Hubbard model only
J.M. is grateful to the Ramón y Cajal program of Ministerio de Ciencia y Tecnología, Spain for financial support through contract CTQ2005-09385. The Lanczos runs were performed on the Jülich BlueGene/L under grant JIFF22