Electronic structure of the high and low pressure polymorphs of MgSiN$_{2}$

TL;DR

This study uses density functional calculations to explore the electronic structure of MgSiN$_{2}$ under pressure, revealing phase transformation and band gap evolution, with implications for its semiconducting properties.

Contribution

It provides detailed computational analysis of pressure-induced phase transition and band gap changes in MgSiN$_{2}$, a material not extensively studied before.

Findings

MgSiN$_{2}$ transforms from wurtzite to rock-salt structure at ~20 GPa

Both phases are wide band gap semiconductors with increasing gaps under pressure

Band gap in LP-MgSiN$_{2}$ surpasses that in HP-MgSiN$_{2}$ at high pressure

Abstract

We have performed density functional calculations on the group II-IV nitride MgSiN$_{2}$. At a pressure of about 20~GPa the ground state wurtzite derived MgSiN$_{2}$ structure (LP-MgSiN$_{2}$) transforms into a rock-salt derived structure (HP-MgSiN$_{2}$) in agreement with previous theoretical and experimental studies. Both phases are wide band gap semiconductors with indirect band gaps at equilibrium of 5.58 eV (LP-MgSiN$_{2}$) and 5.87 eV (HP-MgSiN$_{2}$), respectively. As the pressure increases, the band gaps become larger for both phases, however, the band gap in LP-MgSiN$_{2}$ increases faster than the gap in HP-MgSiN$_{2}$ and with a high enough pressure the band gap in LP-MgSiN$_{2}$ becomes larger than the band gap in HP-MgSiN$_{2}$.