Thermal conductivity of magnesium selenide (MgSe)–A first principles study

Abstract

Wide bandgap semiconductor has recently attracted attraction for power electronics, thermoelectric and high temperature applications. Magnesium Selenide (MgSe) is a wide bandgap semiconductor extensively studied for its electronic, magnetic, optical and structural properties. In this work, we report the temperature and length dependence lattice thermal conductivity of magnesium selenide (MgSe) with different crystallographic phase; zincblende (ZB), rocksalt (RS), wurtzite (WZ) and nickel arsenic (NiAs) using first principles computations. Our first principles calculations results shows a low thermal conductivity of MgSe with kNiAs < krocksalt < kwurtzite < kzincblende. We systematically investigated the elastic constants, phonon frequencies, phonon scattering rate and mode contribution thermal conductivity. Our first principles calculations shows a room temperature low thermal conductivity of 4.54 Wm−1K−1 for the NiAs phase due to the strong phonon–phonon scattering and 21.27 Wm−1 K−1 for the zincblende structure very low phonon–phonon scattering arising from the phonon bandgap. Our results elucidate that MgSe(NiAs) compounds with low thermal conductivity and MgSe(ZB) with high thermal conductivity will be a promising material for thermoelectric applications and thermal management systems respectively.