Crossroads electronic structure of MnS, MnSe, and MnTe

By using the LDA + U method, we have investigated the electronic structure of MnB^VI (B^VI = S, Se, Te)-which are end-point materials for wide gap semiconductors, A_1-x^IIMn_xB ^VI (A^II = Zn, Cd, Hg)-using parameters calculated by the so callled solid atom method. All these MnB^VI compoounds have semiconducting electronic structure in the antiferromagnetic phase. The character of each energy gap is on the cossroads between charge transfer type insulators and band insulators. The LDA + U method yields enhanced energy gaps and magnetic moments, as compared to those of the LDA calculation in agreement with experimental values.