Optical properties of CsCu${}_2$X${}_3$ (X=Cl, Br and I): A comparative study between hybrid time-dependent density-functional theory and the Bethe-Salpeter equation

Abstract

The cesium copper halides CsCu${}_2$X${}_3$ (X=Cl, Br and I) are a class of all-inorganic perovskites with interesting and potentially useful optical properties, characterized by distinct excitonic features. We present a computational study of the optical absorption spectra of CsCu${}_2$X${}_3$, comparing time-dependent density-functional theory (TDDFT) and the Bethe-Salpeter equation (BSE), 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.

References in corpus (5)

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• Many-body perturbation theory calculations using the yambo code
• Self-consistent hybrid functional for condensed systems
• GW quasiparticle band gap of the hybrid organic-inorganic perovskite CH${}_3$NH${}_3$PbI${}_3$: Effect of spin-orbit interaction, semicore electrons, and self-consistency
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• Accurate and efficient prediction of the band gaps and optical spectra of chalcopyrite semiconductors from a non-empirical range-separated dielectric-dependent hybrid: Comparison with many-body perturbation theory
• Metal halide thermoelectrics: prediction of high-performance CsCu2I3
• Wigner-Seitz truncated TDDFT approach for the calculation of exciton binding energies in solids
• Temperature-Dependent Dielectric Function of Calcium Fluoride