Ground state of half-metallic zinc-blende MnAs

In this paper we investigate theoretically the ground-state NiAs-type structure of MnAs and we compare the magnetic and structural properties with a hypothetical zinc-blende structure. A zinc-blende structure can be obtained, in principle, from the diluted magnetic semiconductor Ga_1-xMnₓAs in the limit $x=1.$ Using density-functional calculations within the local spin-density approximation, we show that the zinc-blende structure, although showing half metallic behavior that is very attractive for spintronics, cannot be stabilized at equilibrium. We perform a tight-binding analysis of the Mn-As bond in the tetrahedral coordination to investigate the nature of the bonding in diluted magnetic semiconductors.