2013/02/28 by Zeng-hui Yang, Carsten A. Ullrich · 2 citations
Materials Science · Physics and Astronomy · #Electronic and Structural Properties of Oxides #Quantum and electron transport phenomena #Spectroscopy and Quantum Chemical Studies #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.87.195204
arxiv created 2013/05/08 · openalex publication_date 2013/05/14 · arxiv updated 2013/05/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Excitons are electron-hole pairs appearing below the band gap in insulators and semiconductors. They are vital to photovoltaics, but are hard to obtain with time-dependent density-functional theory (TDDFT), since most standard exchange-correlation (xc) functionals lack the proper long-range behavior. Furthermore, optical spectra of bulk solids calculated with TDDFT often lack the required resolution to distinguish discrete, weakly bound excitons from the continuum. We adapt the Casida equation formalism for molecular excitations to periodic solids, which allows us to obtain exciton binding energies directly. We calculate exciton binding energies for both small- and large-gap semiconductors and insulators, study the recently proposed bootstrap xc kernel [S. Sharma et al., Phys. Rev. Lett. 107, 186401 (2011)], and extend the formalism to triplet excitons.