Calculation of density of states for FeAs-based superconductors

The spectral and the total density of states were calculated for two-dimensional FeAs-clusters within the limits of the two-orbital model, which is widely used for modeling iron-based superconductors. The spectra were restored by means of an asymptotically exact stochastic procedure, which was modified to restore the kernel of the integral equation relating the Matsubara Green's function and the spectral density. The data for Matsubara Green's function were obtained with the use of the generalized quantum world-line Monte Carlo algorithm adapted for the two-orbital model. The calculations were made for clusters with sizes up to $10\times10$ FeAs-cells. The data are presented for the distribution profiles along the main crystallographic directions and for the entire Brillouin zone. The analysis of the doped state revealed differences in the electron and hole states of the system that is correlated with known experimental data.