First-principle study on the surface and interface properties of the half-metallic ferromagnet of rocksalt structural BaC

Recent study showed that rocksalt BaC exhibits half-metallic ferromagnetism (Dong and Zhao, 2011). Here we use the first-principles calculations to investigate the electronic and magnetic properties of the BaC (0 0 1) and (1 1 1) surfaces and the interfaces with the SnSe (1 1 1) substrate. The obtained results reveal that the half-metallicity verified in bulk BaC is preserved at the (0 0 1) and (1 1 1) surfaces. Unfortunately, interfacial configuration shows that the half-metallicity of bulk rocksalt BaC is destroyed for all possible configurations of C-Se, C-Sn, Ba-Se, and Ba-Sn. Moreover, by computing the interface adhesion energies, we evaluate the interfacial adhesive strength for the four possible interfacial structures. We also discuss the changes of the atomic magnetic moments at the (0 0 1) and (1 1 1) surfaces and the interfaces layers with respect to the corresponding bulk values.