2019/05/27 by Mathias Rosdahl Brems, Brems, Mathias Rosdahl, Morten Willatzen +1
Materials Science · #Graphene research and applications #2D Materials and Applications #Ga2O3 and related materials
paper · pdf · doi:10.48550/arxiv.1905.11196
Group theory and density functional theory methods are combined to obtain compact and accurate k⋅ p Hamiltonians that describe the bandstructures around the K and Γ points for the 2D material hexagonal boron arsenide (h-BAs) predicted to be an important low-bandgap material for electric, thermoelectric, and piezoelectric properties that supplements the well-studied 2D material hexagonal boron nitride. Hexagonal boron arsenide is a direct bandgap material with band extrema at the K point. The bandgap becomes indirect with a conduction-band minimum at the Γ point subject to a strong electric field or biaxial strain. At even higher electric field strengths (approximately 0.75 V/Å) or a large strain (14~%) 2D hexagonal boron arsenide becomes metallic. Our k⋅ p models include to leading orders the influence of strain, electric, and magnetic fields. Excellent qualitative and quantitative agreement between density functional theory and k⋅ p predictions are demonstrated for different types of strain and electric fields.