--- _id: '30288' abstract: - lang: eng text: Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients. author: - first_name: Falko full_name: Schmidt, Falko id: '35251' last_name: Schmidt orcid: 0000-0002-5071-5528 - first_name: Agnieszka L. full_name: Kozub, Agnieszka L. id: '77566' last_name: Kozub orcid: https://orcid.org/0000-0001-6584-0201 - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Arno full_name: Schindlmayr, Arno id: '458' last_name: Schindlmayr orcid: 0000-0002-4855-071X citation: ama: 'Schmidt F, Kozub AL, Gerstmann U, Schmidt WG, Schindlmayr A. Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. In: Corradi G, Kovács L, eds. New Trends in Lithium Niobate: From Bulk to Nanocrystals. MDPI; 2022:231-248. doi:10.3390/books978-3-0365-3339-1' apa: 'Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., & Schindlmayr, A. (2022). Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. In G. Corradi & L. Kovács (Eds.), New Trends in Lithium Niobate: From Bulk to Nanocrystals (pp. 231–248). MDPI. https://doi.org/10.3390/books978-3-0365-3339-1' bibtex: '@inbook{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2022, place={Basel}, title={Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}, DOI={10.3390/books978-3-0365-3339-1}, booktitle={New Trends in Lithium Niobate: From Bulk to Nanocrystals}, publisher={MDPI}, author={Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}, editor={Corradi, Gábor and Kovács, László}, year={2022}, pages={231–248} }' chicago: 'Schmidt, Falko, Agnieszka L. Kozub, Uwe Gerstmann, Wolf Gero Schmidt, and Arno Schindlmayr. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” In New Trends in Lithium Niobate: From Bulk to Nanocrystals, edited by Gábor Corradi and László Kovács, 231–48. Basel: MDPI, 2022. https://doi.org/10.3390/books978-3-0365-3339-1.' ieee: 'F. Schmidt, A. L. Kozub, U. Gerstmann, W. G. Schmidt, and A. Schindlmayr, “Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response,” in New Trends in Lithium Niobate: From Bulk to Nanocrystals, G. Corradi and L. Kovács, Eds. Basel: MDPI, 2022, pp. 231–248.' mla: 'Schmidt, Falko, et al. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” New Trends in Lithium Niobate: From Bulk to Nanocrystals, edited by Gábor Corradi and László Kovács, MDPI, 2022, pp. 231–48, doi:10.3390/books978-3-0365-3339-1.' short: 'F. Schmidt, A.L. Kozub, U. Gerstmann, W.G. Schmidt, A. Schindlmayr, in: G. Corradi, L. Kovács (Eds.), New Trends in Lithium Niobate: From Bulk to Nanocrystals, MDPI, Basel, 2022, pp. 231–248.' date_created: 2022-03-13T15:28:47Z date_updated: 2023-04-20T15:58:51Z ddc: - '530' department: - _id: '296' - _id: '230' - _id: '429' - _id: '295' - _id: '15' - _id: '170' - _id: '35' - _id: '790' doi: 10.3390/books978-3-0365-3339-1 editor: - first_name: Gábor full_name: Corradi, Gábor last_name: Corradi - first_name: László full_name: Kovács, László last_name: Kovács language: - iso: eng page: 231-248 place: Basel project: - _id: '53' name: 'TRR 142: TRR 142' - _id: '55' name: 'TRR 142 - B: TRR 142 - Project Area B' - _id: '69' name: 'TRR 142 - B4: TRR 142 - Subproject B4' - _id: '54' name: 'TRR 142 - A: TRR 142 - Project Area A' - _id: '166' name: 'TRR 142 - A11: TRR 142 - Subproject A11' - _id: '168' name: 'TRR 142 - B07: TRR 142 - Subproject B07' - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication: 'New Trends in Lithium Niobate: From Bulk to Nanocrystals' publication_identifier: eisbn: - 978-3-0365-3339-1 isbn: - 978-3-0365-3340-7 publication_status: published publisher: MDPI quality_controlled: '1' status: public title: 'Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response' type: book_chapter user_id: '16199' year: '2022' ...