Bandstructure and optical response of α-Arsenene.

Monolayer group-V structures have been shown to be rich in terms of their topological aspects and how they are protected by symmetries. In particular, density functional theory (DFT) calculations of the α-Sb monolayer show the existence of Dirac points in the band structure due to its non-symmorphic crystal structure. In this talk, we focus on another group-V element, Arsenic, in the monolayer α-form. In particular, we will present its band properties at different levels of theory from DFT to quasi-particle self-consistent GW (QSGW) with and without vertex contributions (ladder diagrams) and with and without spin-orbit coupling (SOC). We also investigate how these properties change as we move from the flat to the puckered α-structure. Moreover, as excitonic effects are important in 2D materials, we study the optical response by means of the Bethe-Salpeter equation (BSE) method.