[{"ddc":["530"],"language":[{"iso":"eng"}],"external_id":{"isi":["000895837200001"]},"abstract":[{"text":"Hole polarons and defect-bound exciton polarons in lithium niobate are investigated by means of density-functional theory, where the localization of the holes is achieved by applying the +U approach to the oxygen 2p orbitals. We find three principal configurations of hole polarons: (i) self-trapped holes localized at displaced regular oxygen atoms and (ii) two other configurations bound to a lithium vacancy either at a threefold coordinated oxygen atom above or at a two-fold coordinated oxygen atom below the defect. The latter is the most stable and is in excellent quantitative agreement with measured g factors from electron paramagnetic resonance. Due to the absence of mid-gap states, none of these hole polarons can explain the broad optical absorption centered between 2.5 and 2.8 eV that is observed in transient absorption spectroscopy, but such states appear if a free electron polaron is trapped at the same lithium vacancy as the bound hole polaron, resulting in an exciton polaron. The dielectric function calculated by solving the Bethe–Salpeter equation indeed yields an optical peak at 2.6 eV in agreement with the two-photon experiments. The coexistence of hole and exciton polarons, which are simultaneously created in optical excitations, thus satisfactorily explains the reported experimental data.","lang":"eng"}],"file":[{"description":"Creative Commons Attribution 4.0 International Public License (CC BY 4.0)","file_size":1762554,"title":"A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate","file_name":"crystals-12-01586-v2.pdf","file_id":"45570","access_level":"open_access","date_updated":"2023-06-12T00:22:51Z","date_created":"2023-06-11T23:59:27Z","creator":"schindlm","relation":"main_file","content_type":"application/pdf"}],"publication":"Crystals","title":"A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate","publisher":"MDPI AG","date_created":"2023-04-20T13:52:44Z","year":"2022","quality_controlled":"1","issue":"11","article_number":"1586","article_type":"original","isi":"1","file_date_updated":"2023-06-12T00:22:51Z","project":[{"name":"TRR 142: TRR 142","_id":"53"},{"_id":"54","name":"TRR 142 - A: TRR 142 - Project Area A"},{"name":"TRR 142 - B: TRR 142 - Project Area B","_id":"55"},{"_id":"69","name":"TRR 142 - B04: TRR 142 - Subproject B04"},{"name":"TRR 142 - B07: TRR 142 - Subproject B07","_id":"168"},{"_id":"166","name":"TRR 142 - A11: TRR 142 - Subproject A11"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"_id":"44088","user_id":"16199","department":[{"_id":"15"},{"_id":"296"},{"_id":"170"},{"_id":"295"},{"_id":"35"},{"_id":"230"},{"_id":"429"},{"_id":"27"}],"status":"public","type":"journal_article","doi":"10.3390/cryst12111586","date_updated":"2025-09-18T13:28:05Z","oa":"1","author":[{"orcid":"0000-0002-5071-5528","last_name":"Schmidt","full_name":"Schmidt, Falko","id":"35251","first_name":"Falko"},{"full_name":"Kozub, Agnieszka L.","id":"77566","orcid":"0000-0001-6584-0201","last_name":"Kozub","first_name":"Agnieszka L."},{"first_name":"Uwe","last_name":"Gerstmann","orcid":"0000-0002-4476-223X","full_name":"Gerstmann, Uwe","id":"171"},{"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"}],"volume":12,"citation":{"apa":"Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., &#38; Schindlmayr, A. (2022). A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate. <i>Crystals</i>, <i>12</i>(11), Article 1586. <a href=\"https://doi.org/10.3390/cryst12111586\">https://doi.org/10.3390/cryst12111586</a>","bibtex":"@article{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2022, title={A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate}, volume={12}, DOI={<a href=\"https://doi.org/10.3390/cryst12111586\">10.3390/cryst12111586</a>}, number={111586}, journal={Crystals}, publisher={MDPI AG}, author={Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2022} }","mla":"Schmidt, Falko, et al. “A Density-Functional Theory Study of Hole and Defect-Bound Exciton Polarons in Lithium Niobate.” <i>Crystals</i>, vol. 12, no. 11, 1586, MDPI AG, 2022, doi:<a href=\"https://doi.org/10.3390/cryst12111586\">10.3390/cryst12111586</a>.","short":"F. Schmidt, A.L. Kozub, U. Gerstmann, W.G. Schmidt, A. Schindlmayr, Crystals 12 (2022).","ieee":"F. Schmidt, A. L. Kozub, U. Gerstmann, W. G. Schmidt, and A. Schindlmayr, “A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate,” <i>Crystals</i>, vol. 12, no. 11, Art. no. 1586, 2022, doi: <a href=\"https://doi.org/10.3390/cryst12111586\">10.3390/cryst12111586</a>.","chicago":"Schmidt, Falko, Agnieszka L. Kozub, Uwe Gerstmann, Wolf Gero Schmidt, and Arno Schindlmayr. “A Density-Functional Theory Study of Hole and Defect-Bound Exciton Polarons in Lithium Niobate.” <i>Crystals</i> 12, no. 11 (2022). <a href=\"https://doi.org/10.3390/cryst12111586\">https://doi.org/10.3390/cryst12111586</a>.","ama":"Schmidt F, Kozub AL, Gerstmann U, Schmidt WG, Schindlmayr A. A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate. <i>Crystals</i>. 2022;12(11). doi:<a href=\"https://doi.org/10.3390/cryst12111586\">10.3390/cryst12111586</a>"},"intvolume":"        12","publication_status":"published","publication_identifier":{"eissn":["2073-4352"]},"has_accepted_license":"1"},{"title":"Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response","date_created":"2022-03-13T15:28:47Z","publisher":"MDPI","year":"2022","quality_controlled":"1","language":[{"iso":"eng"}],"ddc":["530"],"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."}],"publication":"New Trends in Lithium Niobate: From Bulk to Nanocrystals","doi":"10.3390/books978-3-0365-3339-1","author":[{"first_name":"Falko","full_name":"Schmidt, Falko","id":"35251","orcid":"0000-0002-5071-5528","last_name":"Schmidt"},{"last_name":"Kozub","orcid":"https://orcid.org/0000-0001-6584-0201","full_name":"Kozub, Agnieszka L.","id":"77566","first_name":"Agnieszka L."},{"id":"171","full_name":"Gerstmann, Uwe","orcid":"0000-0002-4476-223X","last_name":"Gerstmann","first_name":"Uwe"},{"full_name":"Schmidt, Wolf Gero","id":"468","last_name":"Schmidt","orcid":"0000-0002-2717-5076","first_name":"Wolf Gero"},{"last_name":"Schindlmayr","orcid":"0000-0002-4855-071X","id":"458","full_name":"Schindlmayr, Arno","first_name":"Arno"}],"date_updated":"2025-12-05T14:00:04Z","page":"231-248","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. <i>New Trends in Lithium Niobate: From Bulk to Nanocrystals</i>. MDPI; 2022:231-248. doi:<a href=\"https://doi.org/10.3390/books978-3-0365-3339-1\">10.3390/books978-3-0365-3339-1</a>","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 <i>New Trends in Lithium Niobate: From Bulk to Nanocrystals</i>, edited by Gábor Corradi and László Kovács, 231–48. Basel: MDPI, 2022. <a href=\"https://doi.org/10.3390/books978-3-0365-3339-1\">https://doi.org/10.3390/books978-3-0365-3339-1</a>.","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 <i>New Trends in Lithium Niobate: From Bulk to Nanocrystals</i>, G. Corradi and L. Kovács, Eds. Basel: MDPI, 2022, pp. 231–248.","apa":"Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., &#38; Schindlmayr, A. (2022). Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. In G. Corradi &#38; L. Kovács (Eds.), <i>New Trends in Lithium Niobate: From Bulk to Nanocrystals</i> (pp. 231–248). MDPI. <a href=\"https://doi.org/10.3390/books978-3-0365-3339-1\">https://doi.org/10.3390/books978-3-0365-3339-1</a>","mla":"Schmidt, Falko, et al. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” <i>New Trends in Lithium Niobate: From Bulk to Nanocrystals</i>, edited by Gábor Corradi and László Kovács, MDPI, 2022, pp. 231–48, doi:<a href=\"https://doi.org/10.3390/books978-3-0365-3339-1\">10.3390/books978-3-0365-3339-1</a>.","bibtex":"@inbook{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2022, place={Basel}, title={Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}, DOI={<a href=\"https://doi.org/10.3390/books978-3-0365-3339-1\">10.3390/books978-3-0365-3339-1</a>}, 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} }","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."},"place":"Basel","publication_identifier":{"isbn":["978-3-0365-3340-7"],"eisbn":["978-3-0365-3339-1"]},"publication_status":"published","department":[{"_id":"296"},{"_id":"230"},{"_id":"429"},{"_id":"295"},{"_id":"15"},{"_id":"170"},{"_id":"35"},{"_id":"790"}],"user_id":"16199","_id":"30288","project":[{"name":"TRR 142: TRR 142","_id":"53"},{"_id":"55","name":"TRR 142 - B: TRR 142 - Project Area B"},{"_id":"69","name":"TRR 142 - B4: TRR 142 - Subproject B4"},{"name":"TRR 142 - A: TRR 142 - Project Area A","_id":"54"},{"name":"TRR 142 - A11: TRR 142 - Subproject A11","_id":"166"},{"_id":"168","name":"TRR 142 - B07: TRR 142 - Subproject B07"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"},{"name":"TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen","_id":"53"}],"status":"public","editor":[{"last_name":"Corradi","full_name":"Corradi, Gábor","first_name":"Gábor"},{"first_name":"László","full_name":"Kovács, László","last_name":"Kovács"}],"type":"book_chapter"},{"publication_status":"published","has_accepted_license":"1","publication_identifier":{"eissn":["2073-4352"]},"citation":{"ama":"Schmidt F, Kozub AL, Gerstmann U, Schmidt WG, Schindlmayr A. Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. <i>Crystals</i>. 2021;11:542. doi:<a href=\"https://doi.org/10.3390/cryst11050542\">10.3390/cryst11050542</a>","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.” <i>Crystals</i> 11 (2021): 542. <a href=\"https://doi.org/10.3390/cryst11050542\">https://doi.org/10.3390/cryst11050542</a>.","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,” <i>Crystals</i>, vol. 11, p. 542, 2021, doi: <a href=\"https://doi.org/10.3390/cryst11050542\">10.3390/cryst11050542</a>.","mla":"Schmidt, Falko, et al. “Electron Polarons in Lithium Niobate: Charge Localization, Lattice Deformation, and Optical Response.” <i>Crystals</i>, vol. 11, MDPI, 2021, p. 542, doi:<a href=\"https://doi.org/10.3390/cryst11050542\">10.3390/cryst11050542</a>.","bibtex":"@article{Schmidt_Kozub_Gerstmann_Schmidt_Schindlmayr_2021, title={Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}, volume={11}, DOI={<a href=\"https://doi.org/10.3390/cryst11050542\">10.3390/cryst11050542</a>}, journal={Crystals}, publisher={MDPI}, author={Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}, year={2021}, pages={542} }","short":"F. Schmidt, A.L. Kozub, U. Gerstmann, W.G. Schmidt, A. Schindlmayr, Crystals 11 (2021) 542.","apa":"Schmidt, F., Kozub, A. L., Gerstmann, U., Schmidt, W. G., &#38; Schindlmayr, A. (2021). Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response. <i>Crystals</i>, <i>11</i>, 542. <a href=\"https://doi.org/10.3390/cryst11050542\">https://doi.org/10.3390/cryst11050542</a>"},"page":"542","intvolume":"        11","author":[{"full_name":"Schmidt, Falko","id":"35251","last_name":"Schmidt","orcid":"0000-0002-5071-5528","first_name":"Falko"},{"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","id":"171","full_name":"Gerstmann, Uwe","last_name":"Gerstmann","orcid":"0000-0002-4476-223X"},{"first_name":"Wolf Gero","orcid":"0000-0002-2717-5076","last_name":"Schmidt","id":"468","full_name":"Schmidt, Wolf Gero"},{"first_name":"Arno","id":"458","full_name":"Schindlmayr, Arno","orcid":"0000-0002-4855-071X","last_name":"Schindlmayr"}],"volume":11,"date_updated":"2023-04-21T11:20:15Z","oa":"1","doi":"10.3390/cryst11050542","type":"journal_article","status":"public","user_id":"171","department":[{"_id":"296"},{"_id":"230"},{"_id":"429"},{"_id":"295"},{"_id":"15"},{"_id":"170"},{"_id":"35"},{"_id":"790"}],"project":[{"_id":"53","name":"TRR 142"},{"name":"TRR 142 - Project Area B","_id":"55"},{"_id":"69","name":"TRR 142 - Subproject B4"},{"name":"Computing Resources Provided by the Paderborn Center for Parallel Computing","_id":"52"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"_id":"21946","file_date_updated":"2021-05-13T16:51:41Z","funded_apc":"1","article_type":"original","isi":"1","quality_controlled":"1","year":"2021","date_created":"2021-05-03T09:36:13Z","publisher":"MDPI","title":"Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response","publication":"Crystals","file":[{"date_updated":"2021-05-13T16:51:41Z","date_created":"2021-05-13T16:47:11Z","creator":"schindlm","description":"Creative Commons Attribution 4.0 International Public License (CC BY 4.0)","file_size":3042827,"title":"Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response","file_id":"22163","access_level":"open_access","file_name":"crystals-11-00542.pdf","content_type":"application/pdf","relation":"main_file"}],"abstract":[{"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.","lang":"eng"}],"external_id":{"isi":["000653822700001"]},"language":[{"iso":"eng"}],"ddc":["530"]},{"status":"public","type":"journal_article","article_type":"original","isi":"1","file_date_updated":"2021-11-18T20:49:19Z","_id":"23418","project":[{"_id":"53","name":"TRR 142"},{"_id":"55","name":"TRR 142 - Project Area B"},{"name":"TRR 142 - Subproject B4","_id":"69"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"department":[{"_id":"296"},{"_id":"230"},{"_id":"429"},{"_id":"295"},{"_id":"15"},{"_id":"170"},{"_id":"790"}],"user_id":"171","intvolume":"       104","page":"174110","citation":{"bibtex":"@article{Kozub_Schindlmayr_Gerstmann_Schmidt_2021, title={Polaronic enhancement of second-harmonic generation in lithium niobate}, volume={104}, DOI={<a href=\"https://doi.org/10.1103/PhysRevB.104.174110\">10.1103/PhysRevB.104.174110</a>}, journal={Physical Review B}, publisher={American Physical Society}, author={Kozub, Agnieszka L. and Schindlmayr, Arno and Gerstmann, Uwe and Schmidt, Wolf Gero}, year={2021}, pages={174110} }","short":"A.L. Kozub, A. Schindlmayr, U. Gerstmann, W.G. Schmidt, Physical Review B 104 (2021) 174110.","mla":"Kozub, Agnieszka L., et al. “Polaronic Enhancement of Second-Harmonic Generation in Lithium Niobate.” <i>Physical Review B</i>, vol. 104, American Physical Society, 2021, p. 174110, doi:<a href=\"https://doi.org/10.1103/PhysRevB.104.174110\">10.1103/PhysRevB.104.174110</a>.","apa":"Kozub, A. L., Schindlmayr, A., Gerstmann, U., &#38; Schmidt, W. G. (2021). Polaronic enhancement of second-harmonic generation in lithium niobate. <i>Physical Review B</i>, <i>104</i>, 174110. <a href=\"https://doi.org/10.1103/PhysRevB.104.174110\">https://doi.org/10.1103/PhysRevB.104.174110</a>","chicago":"Kozub, Agnieszka L., Arno Schindlmayr, Uwe Gerstmann, and Wolf Gero Schmidt. “Polaronic Enhancement of Second-Harmonic Generation in Lithium Niobate.” <i>Physical Review B</i> 104 (2021): 174110. <a href=\"https://doi.org/10.1103/PhysRevB.104.174110\">https://doi.org/10.1103/PhysRevB.104.174110</a>.","ieee":"A. L. Kozub, A. Schindlmayr, U. Gerstmann, and W. G. Schmidt, “Polaronic enhancement of second-harmonic generation in lithium niobate,” <i>Physical Review B</i>, vol. 104, p. 174110, 2021, doi: <a href=\"https://doi.org/10.1103/PhysRevB.104.174110\">10.1103/PhysRevB.104.174110</a>.","ama":"Kozub AL, Schindlmayr A, Gerstmann U, Schmidt WG. Polaronic enhancement of second-harmonic generation in lithium niobate. <i>Physical Review B</i>. 2021;104:174110. doi:<a href=\"https://doi.org/10.1103/PhysRevB.104.174110\">10.1103/PhysRevB.104.174110</a>"},"publication_identifier":{"issn":["2469-9950"],"eissn":["2469-9969"]},"has_accepted_license":"1","publication_status":"published","doi":"10.1103/PhysRevB.104.174110","oa":"1","date_updated":"2023-04-21T11:15:30Z","volume":104,"author":[{"orcid":"https://orcid.org/0000-0001-6584-0201","last_name":"Kozub","full_name":"Kozub, Agnieszka L.","id":"77566","first_name":"Agnieszka L."},{"last_name":"Schindlmayr","orcid":"0000-0002-4855-071X","id":"458","full_name":"Schindlmayr, Arno","first_name":"Arno"},{"last_name":"Gerstmann","orcid":"0000-0002-4476-223X","id":"171","full_name":"Gerstmann, Uwe","first_name":"Uwe"},{"orcid":"0000-0002-2717-5076","last_name":"Schmidt","full_name":"Schmidt, Wolf Gero","id":"468","first_name":"Wolf Gero"}],"abstract":[{"lang":"eng","text":"Density-functional theory within a Berry-phase formulation of the dynamical polarization is used to determine the second-order susceptibility χ(2) of lithium niobate (LiNbO3). Defect trapped polarons and bipolarons are found to strongly enhance the nonlinear susceptibility of the material, in particular if localized at NbV–VLi defect pairs. This is essentially a consequence of the polaronic excitation resulting in relaxation-induced gap states. The occupation of these levels leads to strongly enhanced χ(2) coefficients and allows for the spatial and transient modification of the second-harmonic generation of macroscopic samples."}],"file":[{"file_size":804012,"file_name":"PhysRevB.104.174110.pdf","creator":"schindlm","content_type":"application/pdf","description":"© 2021 American Physical Society","title":"Polaronic enhancement of second-harmonic generation in lithium niobate","file_id":"27577","access_level":"open_access","date_updated":"2021-11-18T20:49:19Z","date_created":"2021-11-18T20:49:19Z","relation":"main_file"}],"publication":"Physical Review B","ddc":["530"],"language":[{"iso":"eng"}],"external_id":{"arxiv":["2106.01145"],"isi":["000720931400007"]},"year":"2021","quality_controlled":"1","title":"Polaronic enhancement of second-harmonic generation in lithium niobate","publisher":"American Physical Society","date_created":"2021-08-16T19:09:46Z"},{"type":"journal_article","status":"public","user_id":"16199","department":[{"_id":"296"},{"_id":"230"},{"_id":"429"},{"_id":"295"},{"_id":"288"},{"_id":"15"},{"_id":"170"},{"_id":"35"},{"_id":"790"}],"project":[{"name":"TRR 142","_id":"53"},{"_id":"55","name":"TRR 142 - Project Area B"},{"name":"TRR 142 - Subproject B4","_id":"69"},{"_id":"52","name":"Computing Resources Provided by the Paderborn Center for Parallel Computing"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"_id":"19190","file_date_updated":"2020-10-02T07:37:24Z","isi":"1","article_type":"original","article_number":"043002","publication_status":"published","has_accepted_license":"1","publication_identifier":{"eissn":["2643-1564"]},"citation":{"ama":"Schmidt F, Kozub AL, Biktagirov T, et al. Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations. <i>Physical Review Research</i>. 2020;2(4). doi:<a href=\"https://doi.org/10.1103/PhysRevResearch.2.043002\">10.1103/PhysRevResearch.2.043002</a>","ieee":"F. Schmidt <i>et al.</i>, “Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations,” <i>Physical Review Research</i>, vol. 2, no. 4, Art. no. 043002, 2020, doi: <a href=\"https://doi.org/10.1103/PhysRevResearch.2.043002\">10.1103/PhysRevResearch.2.043002</a>.","chicago":"Schmidt, Falko, Agnieszka L. Kozub, Timur Biktagirov, Christof Eigner, Christine Silberhorn, Arno Schindlmayr, Wolf Gero Schmidt, and Uwe Gerstmann. “Free and Defect-Bound (Bi)Polarons in LiNbO3: Atomic Structure and Spectroscopic Signatures from Ab Initio Calculations.” <i>Physical Review Research</i> 2, no. 4 (2020). <a href=\"https://doi.org/10.1103/PhysRevResearch.2.043002\">https://doi.org/10.1103/PhysRevResearch.2.043002</a>.","apa":"Schmidt, F., Kozub, A. L., Biktagirov, T., Eigner, C., Silberhorn, C., Schindlmayr, A., Schmidt, W. G., &#38; Gerstmann, U. (2020). Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations. <i>Physical Review Research</i>, <i>2</i>(4), Article 043002. <a href=\"https://doi.org/10.1103/PhysRevResearch.2.043002\">https://doi.org/10.1103/PhysRevResearch.2.043002</a>","short":"F. Schmidt, A.L. Kozub, T. Biktagirov, C. Eigner, C. Silberhorn, A. Schindlmayr, W.G. Schmidt, U. Gerstmann, Physical Review Research 2 (2020).","bibtex":"@article{Schmidt_Kozub_Biktagirov_Eigner_Silberhorn_Schindlmayr_Schmidt_Gerstmann_2020, title={Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations}, volume={2}, DOI={<a href=\"https://doi.org/10.1103/PhysRevResearch.2.043002\">10.1103/PhysRevResearch.2.043002</a>}, number={4043002}, journal={Physical Review Research}, publisher={American Physical Society}, author={Schmidt, Falko and Kozub, Agnieszka L. and Biktagirov, Timur and Eigner, Christof and Silberhorn, Christine and Schindlmayr, Arno and Schmidt, Wolf Gero and Gerstmann, Uwe}, year={2020} }","mla":"Schmidt, Falko, et al. “Free and Defect-Bound (Bi)Polarons in LiNbO3: Atomic Structure and Spectroscopic Signatures from Ab Initio Calculations.” <i>Physical Review Research</i>, vol. 2, no. 4, 043002, American Physical Society, 2020, doi:<a href=\"https://doi.org/10.1103/PhysRevResearch.2.043002\">10.1103/PhysRevResearch.2.043002</a>."},"intvolume":"         2","author":[{"orcid":"0000-0002-5071-5528","last_name":"Schmidt","id":"35251","full_name":"Schmidt, Falko","first_name":"Falko"},{"first_name":"Agnieszka L.","last_name":"Kozub","orcid":"https://orcid.org/0000-0001-6584-0201","full_name":"Kozub, Agnieszka L.","id":"77566"},{"last_name":"Biktagirov","id":"65612","full_name":"Biktagirov, Timur","first_name":"Timur"},{"id":"13244","full_name":"Eigner, Christof","orcid":"https://orcid.org/0000-0002-5693-3083","last_name":"Eigner","first_name":"Christof"},{"full_name":"Silberhorn, Christine","id":"26263","last_name":"Silberhorn","first_name":"Christine"},{"id":"458","full_name":"Schindlmayr, Arno","orcid":"0000-0002-4855-071X","last_name":"Schindlmayr","first_name":"Arno"},{"first_name":"Wolf Gero","last_name":"Schmidt","orcid":"0000-0002-2717-5076","full_name":"Schmidt, Wolf Gero","id":"468"},{"first_name":"Uwe","last_name":"Gerstmann","orcid":"0000-0002-4476-223X","full_name":"Gerstmann, Uwe","id":"171"}],"volume":2,"date_updated":"2023-04-20T16:06:21Z","oa":"1","doi":"10.1103/PhysRevResearch.2.043002","publication":"Physical Review Research","file":[{"content_type":"application/pdf","file_size":1955183,"file_name":"PhysRevResearch.2.043002.pdf","creator":"schindlm","relation":"main_file","title":"Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations","description":"Creative Commons Attribution 4.0 International Public License (CC BY 4.0)","file_id":"19843","access_level":"open_access","date_updated":"2020-10-02T07:37:24Z","date_created":"2020-10-02T07:27:38Z"}],"abstract":[{"text":"Polarons in dielectric crystals play a crucial role for applications in integrated electronics and optoelectronics. In this work, we use density-functional theory and Green's function methods to explore the microscopic structure and spectroscopic signatures of electron polarons in lithium niobate (LiNbO3). Total-energy calculations and the comparison of calculated electron paramagnetic resonance data with available measurements reveal the formation of bound \r\npolarons at Nb_Li antisite defects with a quasi-Jahn-Teller distorted, tilted configuration. The defect-formation energies further indicate that (bi)polarons may form not only at \r\nNb_Li antisites but also at structures where the antisite Nb atom moves into a neighboring empty oxygen octahedron. Based on these structure models, and on the calculated charge-transition levels and potential-energy barriers, we propose two mechanisms for the optical and thermal splitting of bipolarons, which provide a natural explanation for the reported two-path recombination of bipolarons. Optical-response calculations based on the Bethe-Salpeter equation, in combination with available experimental data and new measurements of the optical absorption spectrum, further corroborate the geometries proposed here for free and defect-bound (bi)polarons.","lang":"eng"}],"external_id":{"isi":["000604206300002"]},"language":[{"iso":"eng"}],"ddc":["530"],"issue":"4","quality_controlled":"1","year":"2020","date_created":"2020-09-09T09:35:21Z","publisher":"American Physical Society","title":"Free and defect-bound (bi)polarons in LiNbO3: Atomic structure and spectroscopic signatures from ab initio calculations"}]