Analysis of Electrically Detected Magnetic Resonance and Near Zero Field Magnetoresistance Spectra to Identify Spin Defects in GaN

Spin defects in GaN with high-contrast room-temperature optically detected magnetic resonance spectra have recently been discovered [1], with potential applications to quantum sensing. Electrically-active deep-level defects degrade GaN electrical devices [2], and recent measurements via small magnetic field effects at room temperature on the current in GaN have identified signatures of spin blockade in the recombination dynamics that could help identify these defects [3]. We simulate electrically detected magnetic resonance (EDMR) and near zero field magnetoresistance (NZFMR), using Lindblad master equations, and compare with experimental spectra [3] to identify electrically-active spin defects in gallium nitride (GaN) which may have interesting applications in quantum sensing or computation, or may play a role in limiting device performance. Despite the challenge posed by the abundance of nuclear magnetic moments in identifying spin defects with magnetic resonance, we tentatively attribute experimental EDMR and NZFMR spectra to nitrogen and gallium vacancies, using our calculated hyperfine splittings, and provide quantitative analysis. Furthermore, we predict regimes of device operation which may allow for unequivocal identification of these defects. Finally, we present details on our method of classical nuclear hyperfine averaging, which treats the affect of quantum nuclear magnetic moments as an average over a collection of classical magnetic fields, and comment on its immediate application to approximating the nuclear baths of other interesting III-V materials.

[1] J. Luo, Y. Geng, F. Rana, et al., Nat. Mater. 23, 512–518 (2024).

[2] S. J. Pearton, F. Ren, Erin Patrick, et al., ECS J. Solid State Sci. Technol. 5 Q35, 2016.

[3] M. J. Elko, D. T. Hassenmayer, A. A. Higgins et al., J. Vac. Sci. Technol. B; 42 (5): 052205, 2024.