Effect of dynamical screening in the Bethe-Salpeter framework: Excitons in crystalline naphthalene
| Autor: | Zhang, Xiao, Leveillee, Joshua A., Schleife, André |
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| Rok vydání: | 2023 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.107.235205 |
| Popis: | Solving the Bethe-Salpeter equation (BSE) for the optical polarization functions is a first principles means to model optical properties of materials including excitonic effects. One almost ubiquitously used approximation neglects the frequency dependence of the screened electron-hole interaction. This is commonly justified by the large difference in magnitude of electronic plasma frequency and exciton binding energy. We incorporated dynamical effects into the screening of the electron-hole interaction in the BSE using two different approximations as well as exact diagonalization of the exciton Hamiltonian. We compare these approaches for a naphthalene organic crystal, for which the difference between exciton binding energy and plasma frequency is only about a factor of ten. Our results show that in this case, corrections due to dynamical screening are about 15\,\% of the exciton binding energy. We analyze the effect of screening dynamics on optical absorption across the visible spectral range and use our data to establish an \emph{effective} screening model as a computationally efficient approach to approximate dynamical effects in complex materials in the future. Comment: 11 pages main text, 5 figures main text, 9 pages supplemental, 6 figures supplemental |
| Databáze: | arXiv |
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