Spin-polarized first-principles study of ferromagnetism in zinc-blende In1−xMnxSb

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 In1−xMnxSb (x = 0.125, 0.25, 0.50, 0.75, 1.0). The calculated lattice constants of In1−xMnxSb obey the Vegard’s law with a marginal upward bowing. With the increase of Mn concentration in In1−xMnxSb, 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 In1−xMnxSb half-metallic ferromagnets per Mn atom basis is 4μB. 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.