Properties of BSi$_6$N monolayers derived by first-principle computation

TL;DR

This study uses first-principle calculations to explore how BN-bonds influence the structural, electronic, mechanical, thermal, and optical properties of BSi$_6$N monolayers, revealing effects like buckling, bandgap opening, and property modifications.

Contribution

It provides a systematic first-principle analysis of BSi$_6$N monolayers, highlighting how BN-bonds affect stability, electronic structure, and other properties, which was not previously detailed.

Findings

BN-bonds cause high buckling and break sublattice symmetry

BN-bonds open a significant electronic bandgap

Removing BN-bonds reduces buckling and results in smaller bandgap

Abstract

The buckling effects due to BN-bonds in BN-codoped silicene, BSi$_6$N, on structural stability, electronic band structure, and mechanical, thermal and optical properties are studied systematically by first-principle calculations within density functional theory. In the presence of BN-bonds, a high warping in BSi$_6$N indicating a high buckling effect is found due to the presence of a repulsive interaction between B and N atoms. It thus breaks the sublattice symmetry of silicene and opens up a bandgap. The high buckling of BSi$_6$N leads to a decrease in its stiffness and thus induces fractures at small values of applied strain. The finite bandgap caused by the BN-bonds leads to enhancement of the Seebeck coefficient and the figure of merit, and induces a redshift of a peak in the dielectric response. By increasing the distance between the B and N atoms i.e. for the BSi$_6$N without BN-bonds, a flatter BSi$_6$N is found compared to pristine silicene. The stiffness of the structure and the ultimate strain are increased. The breaking of the sublattice symmetry is very weak and a very small bandgap is revealed. As a result, the Seebeck coefficient and the figure of merit stay very small. A reduction in the optical response is seen due to an indirect bandgap.