Spin–orbit coupling effects on the electronic structure of two-dimensional silicon carbide

Abstract

Two-dimensional silicon carbide (2D-SiC) has attracted incredible research attention recently because of its wide bandgap and high exciton binding energy. Here, we focus on the effect of spin–orbit coupling (SOC) on its electronic structure through a detailed first-principles density functional theory study. The calculated electronic band structure and projected electron density of states indicate that Si 3p and C 2p electrons play a vital role in forming the electronic bandgap. The distribution of the real space charge density in the conduction and valence bands further confirms the electronic structure. It is found that inclusion of SOC causes splitting of both the valence and conduction bands. A wide SOC-induced bandgap of ~ 30 meV is observed in this novel material. Moreover, the effect of strain in modulating the bandgap and the SOC interaction is quantified. We find a linear reduction of both the normal and SOC-induced bandgap with increase of the biaxial tensile strain. Bandgap tuning based on such SOC effects may provide a pathway towards future optoelectronic and novel spintronic devices based on 2D-SiC.