Electronic and magnetic properties of transition-metal doped ScN for spintronics applications

Abstract

Motivated by the ongoing interest in nitrides as materials for spintronics applications we have studied effects of doping with magnetic transition-metal elements (T=Cr,Mn,Fe,Co and Ni) on the electronic properties of semiconducting scandium nitride. Using density functional together with the generalized gradient approximation (GGA) as well as PBE0r hybrid functional (with different mixing of the exact exchange), two different doping amounts 25\% ($\rm Sc_{0.75}T_{0.25}N$) and 10\% ($\rm Sc_{0.9}T_{0.1}N$) have been investigated. This is done in comparison to the reference compound ScN with a strong focus on identifying candidates for half-metallic or semiconducting ferromagnetic ground states. Within GGA, only $\rm Sc_{0.75}Cr_{0.25}N$ and $\rm Sc_{0.75}Mn_{0.25}N$ are found to be semiconducting and half-metallic, respectively. The use of hybrid functional changes drastically these finding, where $\rm Sc_{0.75}Fe(Co,Ni)_{0.25}N$ become half-metals and $\rm Sc_{0.75}Cr(Mn)_{0.25}N$ are found both semiconductors. However, additional calculations assuming antiferromagnetic ordering revealed that $\rm Sc_{0.75}Cr_{0.25}N$ is the only compound of this series, which prefers an antiferromagnetic (and semiconducting) ground state. For the lower concentration, $\rm Sc_{0.9}T_{0.1}N$, similar results have been predicted, and all the doped nitrides are found to prefer ferromagnetic ground state over an antiferromagnetic one.