d0 half-metallicity of the bulk and surface (001) of full-Heusler alloy RbSrN2: A first-principle study

First-principle calculations are employed to study the electronic structures and magnetic properties of the RbSrN2 compound with a Cu2MnAl-type Heusler structure. It is determined that RbSrN2 is a new d0 half-metal with an integer magnetic moment of 3 μB in the ferrimagnetic ground state. The HM gap of RbSrN2 is quite large (approximately 0.97 eV); thus, the half-metallicity is robust against lattice distortion and is suitable to be fabricated in the form of thin films. We also reveal that the half-metallicity can be preserved when the Coulomb interactions are considered. In addition, two possible terminations (i.e., N terminated and Rb-Sr terminated) of the surface are considered, and only the one with N atoms in the topmost layer is observed to retain the half-metallic properties of the bulk.