Electronic Structure for Europium Chalcogenides with Modified Becke–Johnson Potential Plus an On-Site Coulomb U (mBJ+U)

Abstract

The full potential linearized-augmented-plane-wave (FP-LAPW) method is generalized to a case of an all-electron fully-relativistic spin-polarized self-consistent band calculation based on the relativistic spin-density functional theory and the modified Becke–Johnson potential (TB-mBJ) plus an on-site coulomb U employed for greater generation of the band gap. The results show that these materials are semiconducting materials. The indirect energy gap obtained in this calculation is 1.63[Formula: see text]eV, 1.79[Formula: see text]eV and 1.96[Formula: see text]eV for EuS, EuSe and EuTe, respectively. It is clear from the plots that LSDA[Formula: see text][Formula: see text][Formula: see text]U is a poor technique for the calculation of the band gaps of chalcogenides (EuX). The calculated results for EuX (S, Se and Te) by mBJ[Formula: see text][Formula: see text][Formula: see text]U are in good agreement with the experimental values as compared to the other calculated results.