2023/10/18 by Zubair, Muhammad, Evangelista, Igor, Khalid, Shoaib +2
#Computational Physics (physics.comp-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · doi:10.48550/arxiv.2310.12094
Two-dimensional materials with Rashba split bands near the Fermi level are key to developing upcoming next-generation spintronics. They enable generating, detecting, and manipulating spin currents without an external magnetic field. Here, we propose BiAs as a novel layered semiconductor with large Rashba splitting in bulk and monolayer forms. Using first-principles calculations, we determined the lowest energy structure of BiAs and its basic electronic properties. Bulk BiAs has a layered crystal structure with two atoms in a rhombohedral primitive cell, similar to the parent Bi and As elemental phases. It is a semiconductor with a narrow and indirect band gap. The spin-orbit coupling leads to Rashba-Dresselhaus spin splitting and characteristic spin texture around the L-point in the Brillouin zone of the hexagonal conventional unit cell, with Rashba energy and Rashba coupling constant for valence (conduction) band of ER= 137 meV (93 meV) and αR= 6.05 eVÅ~(4.6 eVÅ). In monolayer form (i.e., composed of a BiAs bilayer), BiAs has a much larger and direct band gap at Γ, with a circular spin texture characteristic of a pure Rashba effect. The Rashba energy ER= 18 meV and Rashba coupling constant αR= 1.67 eVÅ of monolayer BiAs are quite large compared to other known 2D materials, and these values are shown to increase under tensile biaxial strain.