The Accuracy of a Tuned Screened Range-Separated Hybrid DFT for Describing Electronic and Optical Properties of Defective Semiconductors

Many-body perturbation theory (MBPT) has emerged as a state-of-the-art approach for quantitatively accurate prediction of (opto)electronic properties of materials. However, the computational cost of MBPT motivates the search for simpler methods, particularly those based on density functional theory (DFT), to enable the study of larger and more complex systems. In particular, tuned and screened range-separated hybrid (SRSH) hybrid methods have been shown to provide MBPT accuracy at the cost of hybrid DFT for many materials. We test the accuracy of time-dependent (TD)SRSH for describing the optoelectronic properties of defective semiconductors by the study of point defects in bulk GaN. We first show that the predicted quasiparticle gap and low-energy excitation spectra of (TD)SRSH and MBPT agree well in pristine GaN and GaN containing a single nitrogen vacancy, establishing the accuracy of the method. Aided by the reduced computational cost of (TD)SRSH, we then report on a series of technologically relevant point defects in GaN. This study indicates that TDSRSH is a computationally feasible approach for quantitatively accurate first-principles modeling of defective semiconductors.