Density functional study of excess Fe in ${\text{Fe}}_{1+x}\text{Te}$: Magnetism and doping

Density functional study of excess Fe in ${Fe}_{1 + x} Te$ : Magnetism and doping

Lijun Zhang, D. J. Singh, and M. H. Du

Phys. Rev. B 79, 012506 – Published 27 January 2009

Abstract

The electronic and magnetic properties of the excess Fe in iron telluride ${Fe}_{(1 + x)} Te$ are studied by density functional calculations. We find that the excess Fe occurs with valence near ${Fe}^{+}$ and thus provides electron doping of approximately one carrier per Fe, and furthermore that the excess Fe is strongly magnetic. Thus it will provide local moments that interact with the plane Fe magnetism, and these are expected to persist in phases where the magnetism of the planes is destroyed, for example, by pressure or doping. The results are discussed in the context of superconductivity.