Modeling the half-metallicity of the CrN/GaN (1 1 1) heterostructure

Abstract

Spin-polarized total-energy calculations are employed to investigate the structural, electronic and magnetic properties of the CrN epitaxial growth on the GaN (1 1 1) surface. Cr adsorption and incorporation were considered as initial stages. The adsorption takes place at high symmetry sites, and in the incorporation, Cr replaces Ga. The structures stability is studied with the surface formation energy (SFE) formalism. Results show that in the range from Ga-rich to Ga-poor conditions, and from Cr-rich to Cr-intermediate conditions, the ferromagnetic CrN monolayer is the most stable structure. The interface shows half-metal characteristics, where the minority spins displays a large band-gap. When depositing extra CrN layers, the structure displays the CrN rock-salt phase as the most stable configuration. The epitaxial growth of 2 and 3 CrN layers depicts antiferromagnetic (AFM) characteristics; moreover the interface remains with half-metal properties and Dirac-cone-like features. However, the band-gap of the minority spins is reduced, therefore, it is expected that a large number of CrN bilayers could drive the system to a half-metal to metallic transition. Calculations establish a strategy to generate 100% polarized carriers injection to GaN, which poses this CrN/GaN (1 1 1)||(1 1 1) heterostructure as a component to construct spintronic devices.