Can half metallic zincblende MnAs be grown?
  In this paper we investigate theoretically the ground state NiAs-type structure of MnAs and we compare the magnetic and structural properties with an hypothetical zincblende structure. A zincblende structure can be obtained, in principle, from the diluted magnetic semiconductor Ga$_{1-x}$Mn$_x$As in the limit $x=1$. Using density functional calculations within the local spin-density approximation (LSDA), we show that the zincblende structure, although showing half metallic behavior which is very attractive for spintronics, can not 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. 
Stefano Sanvito and Nicola A. Hill