Tunable magnetism and metallicity in As-doped InSe quadruple layers

Density functional simulation shows that the p z orbital of an isolated As dopant is spin split in an InSe quadruple layer. The coupling between two As atoms can change from antiferromagnetic to ferromagnetic as the distance between them increases, and a cluster of three nearest-neighbor dopants shows half-metal characteristics. Based on these mechanisms, the layer can then be manipulated by As doping into a nonmagnetic/magnetic semiconductor/metal, and even a half-semimetal with a single-spin cone energy band at the Fermi energy.