Origin of the half-metallic band-gap in newly designed quaternary Heusler compounds ZrVTiZ (Z = Al, Ga)

In this work, first-principles calculations have been used to investigate the electronic structures, magnetic properties, and half-metallic nature of the newly designed quaternary Heusler compounds ZrVTiAl and ZrVTiGa. The calculated results reveal that these two compounds are half-metallic ferrimagnets with a total magnetic moment (M-t) of 2 mu(B), and the M-t is in line with the Slater-Pauling curve of M-t = 18 - Z(t), where Z(t) is the total number of valence electrons. Furthermore, via a schematic diagram of the possible d-d hybridization between the transition-metal elements Zr, V, and Ti, we discuss the origin of the half-metallic band gap in the majority spin channel. Also, we have investigated the half-metallic states versus the lattice parameter and the structural stability, i.e., the cohesion energy and formation energy of ZrVTiAl and ZrVTiGa compounds. We hope that our work may trigger Zr-based Heusler compounds for application in future spintronics devices.