The sp² character of new two-dimensional AsB with tunable electronic properties predicted by theoretical studies

As a competitive candidate for replacing graphene that possesses an appropriate fundamental bandgap, structural stability and tunable electronic properties, the recently synthesized honeycomb arsenene has rekindled much enthusiasm in the area of two-dimensional materials. By using first-principles calculations and acoustic phonon limited deformation potential theory, we identify a compelling two-dimensional electronic material, single-layer AsB, which is a direct-gap semiconductor with a bandgap (E_g) of 1.18 eV, almost the same as that of bulk silicon. The orbital projected band structure and electron density as well as partial density of states demonstrate that the frontier state of the planar atomic structural AsB is sp² orbital hybridization, which is distinct from that of buckled arsenene monolayers. Layer thickness, stacking order and strain are effective ways to tune the frontier states, and thus the band structure and bandgap of AsB. Moreover, thicker AsB exhibits one-layer localized states in the AB-stacking structure, which is in sharp contrast to other layered materials such as MoS₂ and phosphorene. Benefiting from the non-localized p_z orbital and larger elastic modulus, the carrier mobility of AsB is in the range of 10³-10⁴ cm² V^-1 s^-1, which is much higher than that of pristine arsenene and some other analogues. Our work provides an effective way to tailor the electronic properties of 2D arsenene, which may open up new avenues for applying it in future nano-optoelectronics and electronics.