Magnetic properties and half-metallic in bulk and (001) surface of Ti2MnAl Heusler alloy with Hg2CuTi-type structure

•The bulk Ti2MnAl alloy exhibits antiferromagnetic half-metallicity.•The half-metallicity is destroyed in five terminations.•The high spin polarization only maintains in TiMn-termination.

Using the first-principles projector augmented wave potential within the generalized gradient approximation, we investigate the magnetic and electronic properties in the bulk and (001) surface of the Heusler alloy Ti2MnAl with Hg2CuTi-type. For the bulk, our calculations indicate that the Heusler alloy Ti2MnAl exhibits antiferromagnetic half-metallicity at the equilibrium lattice constant. Owing to the surface effects, the half-metallicity which can be observed in bulk is destroyed in five terminations. The high spin polarization only maintains in TiMn-termination. Through further studies on the atomic magnetic moments, we find that the moment of surface Ti1 is enhanced obviously, as well as the absolute value of surface Mn atomic moment.