Combined approach of density functional theory and quantum Monte Carlo method to electron correlation in dilute magnetic semiconductors

摘要

We present a realistic study for electronic and magnetic properties in dilutemagnetic semiconductor (Ga,Mn)As. A multi-orbital Haldane-Anderson modelparameterized by density-functional calculations is presented and solved withthe Hirsch-Fye quantum Monte Carlo algorithm. Results well reproduceexperimental results in the dilute limit. When the chemical potential islocated between the top of the valence band and an impurity bound state, along-range ferromagnetic correlations between the impurities, mediated byantiferromagnetic impurity-host couplings, are drastically developed. Weobserve an anisotropic character in local density of states at theimpurity-bound-state energy, which is consistent with the STM measurements. Thepresented combined approach thus offers a firm starting point for realisticcalculations of the various family of dilute magnetic semiconductors.