Spin-polarized first-principles study of ferromagnetism in zinc-blende in1-xMnxSb

摘要

First-principles calculations based on the density functional theory are performed to study the structural properties, spin-polarized electronic band structures, density of states and magnetic properties of the zinc blende In _(1-x) Mn _x Sb (x = 0.125, 0.25, 0.50, 0.75, 1.0). The calculated lattice constants of In_(1-x) Mn _x Sb obey the Vegard's law with a marginal upward bowing. With the increase of Mn concentration in In1-x Mn x Sb, a transition from the semi-metallic to the half-metallic behavior happens such that the majority-spin valence states crosses the Fermi level and the minority-spin states have a gap at the Fermi level. A large exchange splitting (～4 eV) is observed between Mn 3d states of the majority-spins and the minority-spins. The total magnetic moment of In_(1-x)Mn_xSb half-metallic ferromagnets per Mn atom basis is 4μ_B. The total magnetic moment per Mn atom indicate that Mn atoms act as acceptors in InSb and contribute to holes in the lattice of InSb. Due to p-d hybridization, the free space charge of Mn reduces that results a loss in its magnetic moment. The loss in the magnetic moment of the Mn atoms is converted into a small local magnetic moments on the In and Sb sites.