Proceedings of Internet Conference on Theory and Computation of Halide Perovskites (ComPer)
Publication date: 4th September 2020
The cesium copper halides CsCu2X3 are a class of all-inorganic perovskites with interesting and potentially useful optical properties, characterized by distinct excitonic features [1]. We present a computational study of the optical absorption spectra of CsCu2X3, comparing time-dependent density-functional theory (TDDFT) and the Bethe-Salpeter equation (BSE) [2], using GW quasiparticle band structures as input. The TDDFT calculations are carried out using several types of global hybrid exchange-correlation functionals. It is found that an admixture of nonlocal exchange determined by the dielectric constant produces optical spectra in excellent agreement with the BSE. Thus, hybrid TDDFT emerges as a promising first-principles approach for excitonic effects in solids.
This work was supported by NSF grant No. DMR-1810922. The computation for this work was performed on the high performance computing infrastructure pro- vided by Research Computing Support Services at the University of Missouri-Columbia.