Piezospectroscopy and first-principles calculations of the nitrogen-vacancy center in gallium arsenide

Abstract

The nitrogen-vacancy (NV) center occurs in GaAs bulk crystals doped or implanted with nitrogen. The local vibration of nitrogen gives rise to a sharp infrared absorption band at 638 cm${}^{-1}$, exhibiting a fine structure due to the different masses of neighboring ${}^{69}$Ga and ${}^{71}$Ga host isotopes. Piezospectroscopic investigations in the crystallographic <100> direction prove that the center has C${}_{\text{3v}}$ point symmetry, which is weakly perturbed by the isotope effect. The stress-induced shifts of some band components show an unusual non-linear behavior that can be explained by coupling between the isotope and the stress splitting. First-principles density-functional theory calculations are in full accordance with the experiments and confirm the C${}_{\text{3v}}$ symmetry, caused by relaxation of the nitrogen atom from the anion lattice site towards the nearest-neighbor Ga plane. The NV center in GaAs is structurally analogous to the same center in diamond. The $-3$ charge state is most stable for nearly all Fermi-level positions.

References in corpus (1)

• Self-vacancies in Gallium Arsenide: an ab initio calculation