Spectroscopic signatures of nonpolarons: the case of diamond
| Autor: | Joao C. de Abreu, Jean Paul Nery, Matteo Giantomassi, Xavier Gonze, Matthieu J. Verstraete |
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| Přispěvatelé: | UCL - SST/IMCN/MODL - Modelling |
| Rok vydání: | 2022 |
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| Zdroj: | Physical Chemistry Chemical Physics, Vol. 24, no.20, p. 12580-12591 (2022) |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d2cp01012g |
| Popis: | Polarons are quasi-particles made from electrons interacting with vibrations in crystal lattices. They derive their name from the strong electron-vibration polar interaction in ionic systems, that induces associated spectroscopic and optical signatures of such quasi-particles in these materials. In this paper, we focus on diamond, a non-polar crystal with inversion symmetry which nevertheless shows characteristic signatures of polarons, better denoted "nonpolarons" in this case. The polaronic effects are produced by short-range crystal fields with only a small influence of long-range quadrupoles. The many-body spectral function has a characteristic energy dependence, showing a plateau structure that is similar to but distinct from the satellites observed in the polar Fr\"{o}hlich case. The temperature-dependent spectral function of diamond is determined by two methods: the standard Dyson-Migdal approach, which calculates electron-phonon interactions within the lowest-order expansion of the self-energy, and the cumulant expansion, which includes higher orders of electron-phonon interactions. The latter corrects the nonpolaron energies and broadening, providing a more realistic spectral function, which we examine in detail for both conduction and valence band edges. Comment: 10 pages 16 Figures + Subfigures 2 Tables 82 References Supplementary Information (SI) at the end: SI 10 pages SI 14 Figures + Subfigures SI 1 Table |
| Databáze: | OpenAIRE |
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