First-principles studies of point defects in semiconductors using time-dependent density functional theory

First-principles calculations can be used to accelerate the discovery of point defects in semiconductors and insulators, with applications for solid-state quantum technologies. However, the simulation of the optical properties of point-defects, e.g., of photoluminescence (PL) spectra [1], is still a difficult task because it is challenging to obtain an accurate description of multi-configurational excited potential energy surfaces of defects in solids. Here we discuss the calculations of excited states and PL spectra of defects in diamond and hexagonal boron nitride, carried out using an efficient implementation of forces at the level of time-dependent hybrid density functional theory (TDDFT) for periodic systems. The comparison of our results with experiments suggests that TDDFT with hybrid functionals can be used for robust predictions of the excited state properties of point defects in semiconductors.

[1] Y. Jin, M. Govoni, G. Wolfowicz, S. E. Sullivan, F. J. Heremans, D. D. Awschalom, and G. Galli, Phys. Rev. Mater. 5, 084603 (2021)