[Zurück]

T. Ribic, G. Rohringer, K. Held:
"Nonlocal correlations and spectral properties of the Falicov-Kimball model";
Physical Review B, 93 (2016), 195105; S. 195105-1 - 195105-11.

We derive an analytical expression for the local two-particle vertex of the Falicov-Kimball model, including its dependence on all three frequencies, the full vertex, and all reducible vertices. This allows us to calculate the self-energy in diagrammatic extensions of dynamical mean field theory, specifically in the dual fermion
and the one-particle irreducible approach. Nonlocal correlations are thence included and originate here from charge-density wave fluctuations. At low temperatures and in two dimensions, they lead to a larger self-energy contribution at low frequencies and a more insulating spectrum.

http://dx.doi.org/10.1103/PhysRevB.93.195105