BaAs3: a narrow gap 2D semiconductor with vacancy-induced semiconductor–metal transition from first principles

Abstract

Searching for novel two-dimensional (2D) materials is highly desired in the field of nanoelectronics. We here predict a new 2D crystal barium triarsenide (BaAs₃) with a series of encouraging functionalities within density functional theory. Being kinetically and thermally stable, the monolayer and bilayer forms of BaAs₃ possess narrow indirect band gaps of 0.74 eV and 0.34 eV, respectively, with high hole mobilities on the order of ~ 10³ cm² V⁻¹ s⁻¹. The electronic properties of 2D BaAs₃ can be manipulated by controlling the layer thickness. The favorable cleavage energy reveals that layered BaAs₃ can be produced as a freestanding 2D material. Furthermore, by introducing vacancy defects monolayer BaAs₃ can be transformed from a semiconductor to a metal. Two-dimensional BaAs₃ may find promising applications in nanoelectronic devices, such as memristors.