Electronic structure and magnetic properties for iron deficient TlFe2−xSe2 compounds are studied by first-principles calculations. We find that for the case of x=0.5 with a Fe-vacancy ordered orthorhombic superstructure, the ground state exhibits a stripe-like antiferromagnetic ordering and opens a sizable band gap if the short-ranged Coulomb interaction of Fe-3d electrons is moderately strong, manifesting a possible Mott insulating state. While increasing Fe-vacancies from the x=0 side, where the band structure is similar to that of a heavily electron-doped FeSe system, the Mott localization can be driven by kinetic energy reduction as evidenced by the band narrowing effect. Implications of this scenario in the recent experiments on TlFe2−xSe2 are discussed.
@article{arxiv.1101.0533,
title = {Electronic Structure and Mott Localization in Iron Deficient TlFe$_{1.5}$Se$_2$ with Superstructures},
author = {Chao Cao and Jianhui Dai},
journal= {arXiv preprint arXiv:1101.0533},
year = {2011}
}