Strong ferromagnetism of two-dimensional δ-(Zn,Cr)S with shape deformation in both PBE and LDA+U calculations

With density functional calculations, the enhancement of magnetic exchange energy (MEE) of two-dimensional (2-d) diluted magnetic semiconductor (DMS) δ-(Zn,Cr)S with shape deformation was investigated. The increase of lattice parameter c (perpendicular to the Cr layer) and decrease of a (parallel to the Cr layer) had a significant effect on the increase of MEE. Both PBE and LDA + U methods could enhance the MEE to a significant extent, which makes it superior to other δ-DMS found in initial research. The main mechanism by which increase the MEE is to vary the hole-states across the Fermi level with shape deformation, based on Zener's double exchange (DE) mechanism. This enriches the research into 2-d FM materials, which are candidates for next-generation electronic and optoelectronic applications.