Vertex corrections to the electrical conductivity of the Falicov-Kimball model
V. Pokorn´y and V. Janiˇs
Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, CZ-18221 Praha, Czech Republic, E–mail: pokornyv@fzu.cz
We use a systematic expansion around the mean-field solution via the asymptotic limit to high spatial dimensions to study effects of elas- tic scatterings of mobile electrons on either thermally equilibrated or frozen, randomly distributed static impurities. We concentrate on quan- tum coherence effects and calculate the leading-order vertex corrections to the mean-field (Drude) electrical conductivity. We demonstrate that the sign of the vertex correction is always negative and the quantum coherence due to elastic backscatterings always leads to diminution of diffusion. The cases of Falicov-Kimball model with symmetric binary disorder and box disorder are studied.
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