First Principle Study of MC (M = Al, Ga and In) at Equilibrium and under Negative Stress

The electronic and magnetic properties of the hypothetical compounds of mc (m = al, ga and in) are investigated by using firstprinciple calculations and pseudo potential plane wave self-consistent field method based on density functional theory. in order to find the most stable phase of mc (m = al, ga and in), we study them in zinc-blende (zb), rock salt (rs), wurtzite and nias crystal structures. comparison of the total energies of these compounds indicates that rs structure is the most stable crystal structure. our calculations show that these compounds are metals in all of these structures. however, many of the nanospintronic devices are the heterojunctions of halfmetals and semiconductors where the crystal structures of the layers that are grown on the semiconductors are the same as that of the semiconductors. since most of the semiconductors have zb structure, we investigate the electronic and magnetic properties of these compounds in this structure. it is also shown that although mc (m = al, ga and in) compounds are metals in zb structure, they will find half-metal structure when relatively high negative stresses are applied over them. therefore these compounds could be used in spintronic devices.