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

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${2}$.