Two-dimensional silicon carbide structure under uniaxial strains, electronic and bonding analysis

Based on Density Functional Theory (DFT) calculations, the narrowed band gap of two-dimensional (2D) SiC planar structure was investigated under uniaxial strains applied along the zigzag and armchair directions. 2D SiC structure exhibits an indirect band gap in its pristine state which undergoes towards direct band gap at - 10.35% compressive zigzag strain and vanishes below - 16.87% leading to its metallization. The unidirectional strain, applied along the zigzag direction, induces the closure of Si-C-Si bond angle bending from 120 degrees to 99 degrees promoting the increase of the ionic character of the disynaptic (Si-C) atomic basin while reducing the covalent character observed in the pristine structure as revealed by electron localization function (ELF). Additionally, the strain imposed along the zigzag direction, promotes the appearance of weak interactions in regions where there is no absence of strain by means of non-covalent interactions (NCI) index. These non-covalent interactions promote the stability of 2D SiC planar structure under strain regime as recently observed in its three dimensional counterpart (3C SiC). Our structural-electronic-bonding analysis shows that the band gap engineering can be monitored by unidirectional strain regime optimizing the narrowed band gap opening potential routes on the band gap engineering of 2D semiconductor materials with applications in the new generation of electronic devices.