Restoration of density of states for FeAs-based superconductors

Abstract

The spectral and total electron density of states were calculated for two-dimensional FeAs-clusters modeling iron-based superconductors, with use of the generalized quantum Monte Carlo algorithm within the limits of the two-orbital model. The spectra have been obtained by means of the stochastic procedure, which was modified to restore the kernel of the integral equation relating the Matsubara Green's function and the spectral density. The calculations were made for clusters with sizes up to 10 × 10 FeAs-cells. The data on the total density of states near the Fermi level are obtained. There are two branches of the quasiparticle spectrum on both sides of the Fermi level. The effect of the values of the interaction parameter, the cluster size and temperature on the excitation spectra is discussed.