A systematic investigation on the surface properties of Ti2AlC via first-principles calculations

In this study, the surface properties of Ti2AlC surface with different configurations were systematically investigated based on the analysis of surface energy and electronic structure via first-principles calculations. 18 Ti2AlC surface models of basal, prismatic or pyramidal planes were constructed and calculated. The results show that either the Ti(C)- or Al-terminated (0001) surface exhibits the lowest surface energy and highest thermodynamic stability depending on the element chemical potential. While the C-terminated (0001) surface exhibits the lowest thermodynamic stability independent of the element chemical potential. Since the atomic structures of (101¯0) and (112¯0) prismatic planes are similar to those of (101¯1)∼(101¯6) and (112¯1)∼(112¯6) pyramidal planes, respectively, they have similar surface energy and stability. The electronic structure calculations revealed that the highest thermodynamic stability of Ti(C)- or Al-terminated (0001) surface is due to their less structure relaxations. The present first-principles calculation results are well consistent with previous experimental results, and could provide theoretical guidance for the further engineering application of Ti2AlC phase.