Structure and lattice dynamics of the wide band gap semiconductors MgSiN$_{2}$ and MgGeN$_{2}$

M. RÃ¥sander; J. B. Quirk; T. Wang; S. Mathew; R. Davies; R. Palgrave; M. A. Moram

doi:10.1063/1.4985775

paper

Structure and lattice dynamics of the wide band gap semiconductors MgSiN $_{2}$ and MgGeN $_{2}$

arXiv:1705.01515 · doi:10.1063/1.4985775

Abstract

We have determined the structural and lattice dynamical properties of the orthorhombic, wide band gap semiconductors MgSiN $_{2}$ and MgGeN $_{2}$ using density functional theory. In addition, we present structural properties and Raman spectra of a MgSiN $_{2}$ powder. The structural properties and lattice dynamics of the orthorhombic systems are compared to wurtzite AlN. We find clear differences in the lattice dynamics between MgSiN $_{2}$ , MgGeN $_{2}$ and AlN, for example we find that the highest phonon frequency in MgSiN $_{2}$ is about 100~cm $^{- 1}$ higher than the highest frequency in AlN and that MgGeN $_{2}$ is much softer. We also provide the Born effective charge tensors and dielectric tensors of MgSiN $_{2}$ , MgGeN $_{2}$ and AlN. Phonon related thermodynamic properties, such as the heat capacity and entropy, are in very good agreement with available experimental results.

9 pages, 11 figures, 6 tables

Structure and lattice dynamics of the wide band gap semiconductors MgSiN2​ and MgGeN2​

Abstract

Structure and lattice dynamics of the wide band gap semiconductors MgSiN $_{2}$ and MgGeN $_{2}$