Robust half-metallic ferromagnet of cubic VGe3Si4

Abstract

To seek half-metallic ferromagnets compatible with the GeSi semiconductor, we use state-of-the-art density-functional-theory methods to study cubic $\mathrm{VG}{\mathrm{e}}_3\mathrm{S}{\mathrm{i}}_4$. After optimizing its crystal structure with various magnetic orders considered, we find the ferromagnetic structure is the ground state phase and investigate its stability, and then study its spin-resolved electronic structure with an improved method. Our calculated results show that the cubic $\mathrm{VG}{\mathrm{e}}_3\mathrm{S}{\mathrm{i}}_4$ is a half-metallic ferromagnet with half-metallic gap 350 meV, and it is structurally stable against deformations and magnetically robust against antiferromagnetic fluctuations. These results make us believe that the cubic $\mathrm{VG}{\mathrm{e}}_3\mathrm{S}{\mathrm{i}}_4$ could be synthesized as good thin films soon and used in practical spintronic devices.