Effects of Cr doping in δ-MoN: structural, magnetic and spin transport properties

Abstract

Structural, magnetic, and spin transport properties of δ-MoN with one Cr atom substituted at different Mo sites (2a and 6c in the International Tables) have been studied by spin-polarized first-principles calculations and nonequilibrium Green’s function method. The Cr dopants located at 2a and 6c sites [corresponding to the configurations of Cr-MoN(2a) and Cr-MoN(6c)] lead to significant spin splitting of the density of states and contribute 2.86 and 2.70 μB magnetic moments, respectively. Detailed analysis reveals that interactions between the Cr dopant and its neighboring Mo atoms play crucial roles in the magnetic properties of Cr-MoN(2a) and Cr-MoN(6c). The Cr substitution induces evident antiferromagnetic polarization to its Mo neighbors, and each Mo atom possesses − 0.02 to − 0.51 μB magnetic moment antiparallel to the magnetic moment of the Cr dopant. Unlike the pure δ-MoN, the spin-up and the spin-down currents of the Cr-doped systems exhibit obvious spin polarization, and the spin-polarized effect is more enhanced when the Cr dopant is located at the 6c site. Under the examined bias range of 0–1.0 V, Cr-MoN(2a) displays no more than 6.5% spin polarization, whereas in Cr-MoN(6c) case, up to 22.8% of the spin polarization is attained.