Electronic structure and half-metallicity of the Heusler alloy Co2ZrGe

Abstract

The site preference, the electronic structure and the magnetic properties of Co2ZrGe have been studied by using first-principles calculations, and the stabilities of the Cu2MnAl-type and the Hg2CuTi-type structures have been tested in this respect. The Cu2MnAltype structure is more favorable than the Hg2CuTitype structure for the Co2ZrGe compound, and the equilibrium lattice parameter of the Cu2MnAltype Co2ZrGe alloy is 6.06 A. The Co2ZrGe alloy is found to have an energy gap in the minority spin direction at the Fermi level (E F ) and the majority spin band shows strongly metallic characteristic. As a result, the Co2ZrGe alloy is predicted to be a half-metal with 100% spin polarization of the conduction electrons at the E F . The calculated total magnetic moment is 2.00µ B per unit cell, which is in line with the Slater-Pauling curve of M t = Z t − 24. The Co atom-projected spin moment is 1.02µ B , which mainly determines the total moment. Simultaneously, the Zr and the Ge atom moments are −0.08µ B and 0.04µ B , respectively. The Co2ZrGe alloy may be a promising material for application in future spintronics devices.