Structure and phonons of ZnGeN2 -: art. no. 155202

First-principles calculations of the structural relaxation and the phonons at Gamma are presented for ZnGeN2 and compared with those in GaN in terms of Brillouin zone folding effects. Excellent agreement is obtained between various computational methods and experimental data for the structure. Good agreement is obtained with the published experimental Raman spectrum, which shows a superposition of various modes due to limited resolution and significant effects due to second harmonic modes. The Zn-N and Ge-N bond relaxations are found to strongly influence the phonon spectrum at Gamma by widening the range of optical modes.