Investigating the electronic and structural properties of stanene

Abstract

This study investigates the structural and electronic properties of two-dimensional tin, known as stanene, under compressive biaxial strain using Density Functional Theory (DFT). Stanene possesses a buckled honeycomb-like structure and is a potential candidate for a quantum spin Hall (QSH) insulator in which a quantum Hall effect is generated in the absence of a magnetic field due to strong spin-orbit coupling (SOC). This effect, in combination with a strain-tunable band gap, makes stanene an interesting material for spintronic applications. Stanene is stable in both a high-buckled (HB) configuration, which is metallic, and a low-buckled (LB) configuration, which gives rise to a QSH insulating phase, and a transition between the two can be induced through strain. For a monolayer of tin, the HB phase is more stable. This study then investigates whether multiple layers of tin can ensure the LB phase remains the most stable configuration. This work is achieved using the plane-wave pseudopotential code, ABINIT, which can accurately reproduce all-electron calculations of ground-state energies and densities which are then used to determine the ground state structural and electronic properties. A Becke-Johnson correction to band structure calculations is also introduced in order improve the band structure eigenvalues of the LB phase of stanene.