Spatial structure of the in-gap defect wave function induced by a nitrogen vacancy in wurzite GaN and its hyperfine coupling to nearby nuclei in the lattice.

Gallium nitride (GaN) is considered to be a `naturally radiation hard'[1] material with a large direct band gap around 3.6eV, making it of central focus for use in power- and opto-electronics. Consequently, GaN is being actively developed for application in radiation intensive environments that cause lattice structural damage, resulting in the formation of many types of intrinsic point defects. It is well known that defects are able to introduce localized anisotropic states that are able to influence device performance even when present in low number. In GaN, the nitrogen vacancy ($V_N$) is a native point defect of particular interest[2] that is likely to be present in irradiated samples. Understanding the behavior and structure of $V_N$ in bulk GaN is an important step towards understanding the aggregate behavior of these defects in higher densities or when located in active device regions, such as in heterojunctions. We use multiband real space Green's functions to exactly solve the Dyson equation for a localized perturbative potential. We present calculations of simulated cross-sectional STM and hyperfine coupling constants. These quantities directly affect electrically-detected magnetic resonance signals, which can be used to identify these defects when induced in GaN devices.

[1]S. J. Pearton and F. Ren, E. Patrick, M. E. Law and A. Y. Polyakov, ECS J. Solid State Sci. Technol. 5, Q35 (2015)

[2]K. Sagisaka, O. Custance, N.Ishida ,T. Nakamura and Y. Koide, Phys. Rev. B Condens. Matter 106, 115309 (2022)