Half-metallic ferromagnetism in Wurtzite MS (M = Li, Na, and K)

The magnetic properties of MS (M = Li, Na, K) compounds in a Wurtzite structure at zero pressure are investigated by using first principle calculations and the pseudopotential self-consistent method based on density functional theory. It is shown that MS compounds in Wurtzite structure are half-metallic ferromagnets with a magnetic moment of μB per formula unit and half-metallic gaps of 0.24, 0.52, and 0.62 eV for LiS, NaS, and KS, respectively. We also consider the effect of pressure on the half-metallicity of these compounds and we find that LiS, NaS, and KS in Wurtzite structure maintain their half-metallicity up to lattice compressions of 9%, 37%, and 60%, respectively, and as a result one can grow them over the semiconductors in Wurtzite structures that are produced experimentally. These properties cause Wurtzite MS compounds to be appropriate choices to create useful devices in spintronics.