Electronic and optical properties of arsenic monolayers: from planar honeycomb to the puckered phase

TL;DR

This study explores the electronic and optical properties of arsenic monolayers across different structural phases using advanced computational methods, revealing how strain induces phase transitions and affects their optical responses.

Contribution

It provides a comprehensive analysis of arsenic monolayers' properties in various phases, including the effects of strain, spin-orbit coupling, and orbital composition, using state-of-the-art theoretical techniques.

Findings

Transformation from puckered to flat honeycomb structure under strain.

Evolution of band structure and optical response linked to band inversions.

Identification of the orbital origin of low-lying excitons.

Abstract

Group-V monolayer materials exhibit intriguing electronic and optical properties, influenced by their unique crystal symmetries and structural phases. In this work, we study arsenic monolayers, investigating their electronic and optical properties across different phases, including planar, and puckered forms, using density functional theory (DFT) and quasi-particle self-consistent $GW$ (QS$GW$) methods, with and without vertex contributions (ladder diagrams) and examine the effects of spin-orbit coupling and the orbital composition of the bands. The Bethe-Salpeter equation (BSE) method is used to study the optical response and the band origin of the low lying excitons is determined. The gradual transformation from the puckered $\alpha$-phase to the flat honeycomb structure is studied under biaxial strain and the evolution of the band structure and optical response is described in terms of band inversions of bands of different orbital character.