[{"oa_version":"Published Version","_id":"21382","year":"2026","title":"Flexoelectric domain walls enable charge separation and transport in cubic perovskites","article_processing_charge":"Yes","month":"02","pmid":1,"status":"public","scopus_import":"1","date_published":"2026-02-16T00:00:00Z","abstract":[{"lang":"eng","text":"The exceptional energy-harvesting efficiency of lead-halide perovskites arises from unusually long photocarrier diffusion lengths and recombination lifetimes that persist even in defect-rich, solution-grown samples. Paradoxically, perovskites are also known for having very short exciton decay times. Here, we resolve this apparent contradiction by showing that key optoelectronic properties of perovskites can be explained by localized flexoelectric polarization confined to interfaces between domains of spontaneous strain. Using birefringence imaging, electrochemical staining, and zero-bias photocurrent measurements, we visualize the domain structure and directly probe the associated internal fields in nominally cubic single crystals of methylammonium lead bromide. We demonstrate that localized flexoelectric fields spatially separate electrons and holes to opposite sides of domain walls, exponentially suppressing recombination. Domain walls thus act as efficient mesoscopic transport channels for long-lived photocarriers, microscopically linking structural heterogeneity to charge transport and offering mechanistically informed design principles for perovskite solar-energy technologies."}],"ddc":["530"],"acknowledgement":"We are grateful to A. G. Volosniev for the valuable discussions. We thank D. Milius for the assistance with microscopy. D. R. would like to thank F. Filakovský and T. Čuchráč for the valuable discussions. This research was supported by the Scientific Service Units (SSU) of ISTA through resources provided by the Imaging & Optics Facility (IOF) and the Miba Machine Shop Facility (MS).","OA_type":"gold","license":"https://creativecommons.org/licenses/by/4.0/","author":[{"last_name":"Rak","id":"70313b46-47c2-11ec-9e88-cd79101918fe","full_name":"Rak, Dmytro","first_name":"Dmytro"},{"id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","full_name":"Lorenc, Dusan","first_name":"Dusan","last_name":"Lorenc"},{"last_name":"Balazs","orcid":"0000-0001-7597-043X","first_name":"Daniel","full_name":"Balazs, Daniel","id":"302BADF6-85FC-11EA-9E3B-B9493DDC885E"},{"full_name":"Zhumekenov, Ayan A.","first_name":"Ayan A.","last_name":"Zhumekenov"},{"full_name":"Bakr, Osman M.","first_name":"Osman M.","last_name":"Bakr"},{"orcid":"0000-0002-7183-5203","last_name":"Alpichshev","full_name":"Alpichshev, Zhanybek","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","first_name":"Zhanybek"}],"publication_status":"published","article_type":"original","oa":1,"user_id":"ba8df636-2132-11f1-aed0-ed93e2281fdd","file":[{"date_updated":"2026-03-02T14:27:56Z","file_name":"2026_NatureComm_Rak.pdf","success":1,"checksum":"dd7a98de892d0b5abefca7e290ca0f77","file_id":"21390","file_size":2570918,"relation":"main_file","content_type":"application/pdf","access_level":"open_access","date_created":"2026-03-02T14:27:56Z","creator":"dernst"}],"volume":17,"DOAJ_listed":"1","citation":{"short":"D. Rak, D. Lorenc, D. Balazs, A.A. Zhumekenov, O.M. Bakr, Z. Alpichshev, Nature Communications 17 (2026).","ista":"Rak D, Lorenc D, Balazs D, Zhumekenov AA, Bakr OM, Alpichshev Z. 2026. Flexoelectric domain walls enable charge separation and transport in cubic perovskites. Nature Communications. 17, 946.","mla":"Rak, Dmytro, et al. “Flexoelectric Domain Walls Enable Charge Separation and Transport in Cubic Perovskites.” <i>Nature Communications</i>, vol. 17, 946, Springer Nature, 2026, doi:<a href=\"https://doi.org/10.1038/s41467-026-68660-5\">10.1038/s41467-026-68660-5</a>.","apa":"Rak, D., Lorenc, D., Balazs, D., Zhumekenov, A. A., Bakr, O. M., &#38; Alpichshev, Z. (2026). Flexoelectric domain walls enable charge separation and transport in cubic perovskites. <i>Nature Communications</i>. Springer Nature. <a href=\"https://doi.org/10.1038/s41467-026-68660-5\">https://doi.org/10.1038/s41467-026-68660-5</a>","ieee":"D. Rak, D. Lorenc, D. Balazs, A. A. Zhumekenov, O. M. Bakr, and Z. Alpichshev, “Flexoelectric domain walls enable charge separation and transport in cubic perovskites,” <i>Nature Communications</i>, vol. 17. Springer Nature, 2026.","ama":"Rak D, Lorenc D, Balazs D, Zhumekenov AA, Bakr OM, Alpichshev Z. Flexoelectric domain walls enable charge separation and transport in cubic perovskites. <i>Nature Communications</i>. 2026;17. doi:<a href=\"https://doi.org/10.1038/s41467-026-68660-5\">10.1038/s41467-026-68660-5</a>","chicago":"Rak, Dmytro, Dusan Lorenc, Daniel Balazs, Ayan A. Zhumekenov, Osman M. Bakr, and Zhanybek Alpichshev. “Flexoelectric Domain Walls Enable Charge Separation and Transport in Cubic Perovskites.” <i>Nature Communications</i>. Springer Nature, 2026. <a href=\"https://doi.org/10.1038/s41467-026-68660-5\">https://doi.org/10.1038/s41467-026-68660-5</a>."},"type":"journal_article","related_material":{"link":[{"url":"https://ista.ac.at/en/news/explaining-next-generation-solar-cells/","description":"News on ISTA website","relation":"press_release"}]},"publisher":"Springer Nature","doi":"10.1038/s41467-026-68660-5","day":"16","publication":"Nature Communications","publication_identifier":{"eissn":["2041-1723"]},"quality_controlled":"1","language":[{"iso":"eng"}],"intvolume":"        17","corr_author":"1","external_id":{"pmid":["41698893"]},"has_accepted_license":"1","OA_place":"publisher","date_updated":"2026-04-28T12:12:46Z","PlanS_conform":"1","department":[{"_id":"ZhAl"},{"_id":"LifeSc"}],"article_number":"946","file_date_updated":"2026-03-02T14:27:56Z","date_created":"2026-03-02T10:06:58Z","acknowledged_ssus":[{"_id":"Bio"},{"_id":"M-Shop"}],"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"}},{"citation":{"short":"D. Lorenc, A. Volosniev, A.A. Zhumekenov, S. Lee, M. Ibáñez, O.M. Bakr, M. Lemeshko, Z. Alpichshev, ACS Photonics 12 (2025) 5220–5230.","ieee":"D. Lorenc <i>et al.</i>, “Observation of analogue dynamic Schwinger effect and non-perturbative light sensing in lead halide perovskites,” <i>ACS Photonics</i>, vol. 12, no. 9. American Chemical Society, pp. 5220–5230, 2025.","mla":"Lorenc, Dusan, et al. “Observation of Analogue Dynamic Schwinger Effect and Non-Perturbative Light Sensing in Lead Halide Perovskites.” <i>ACS Photonics</i>, vol. 12, no. 9, American Chemical Society, 2025, pp. 5220–30, doi:<a href=\"https://doi.org/10.1021/acsphotonics.5c01360\">10.1021/acsphotonics.5c01360</a>.","apa":"Lorenc, D., Volosniev, A., Zhumekenov, A. A., Lee, S., Ibáñez, M., Bakr, O. M., … Alpichshev, Z. (2025). Observation of analogue dynamic Schwinger effect and non-perturbative light sensing in lead halide perovskites. <i>ACS Photonics</i>. American Chemical Society. <a href=\"https://doi.org/10.1021/acsphotonics.5c01360\">https://doi.org/10.1021/acsphotonics.5c01360</a>","ista":"Lorenc D, Volosniev A, Zhumekenov AA, Lee S, Ibáñez M, Bakr OM, Lemeshko M, Alpichshev Z. 2025. Observation of analogue dynamic Schwinger effect and non-perturbative light sensing in lead halide perovskites. ACS Photonics. 12(9), 5220–5230.","ama":"Lorenc D, Volosniev A, Zhumekenov AA, et al. Observation of analogue dynamic Schwinger effect and non-perturbative light sensing in lead halide perovskites. <i>ACS Photonics</i>. 2025;12(9):5220-5230. doi:<a href=\"https://doi.org/10.1021/acsphotonics.5c01360\">10.1021/acsphotonics.5c01360</a>","chicago":"Lorenc, Dusan, Artem Volosniev, Ayan A. Zhumekenov, Seungho Lee, Maria Ibáñez, Osman M. Bakr, Mikhail Lemeshko, and Zhanybek Alpichshev. “Observation of Analogue Dynamic Schwinger Effect and Non-Perturbative Light Sensing in Lead Halide Perovskites.” <i>ACS Photonics</i>. American Chemical Society, 2025. <a href=\"https://doi.org/10.1021/acsphotonics.5c01360\">https://doi.org/10.1021/acsphotonics.5c01360</a>."},"volume":12,"publisher":"American Chemical Society","day":"11","doi":"10.1021/acsphotonics.5c01360","page":"5220-5230","type":"journal_article","publication":"ACS Photonics","language":[{"iso":"eng"}],"quality_controlled":"1","intvolume":"        12","publication_identifier":{"eissn":["2330-4022"]},"has_accepted_license":"1","OA_place":"publisher","date_updated":"2025-12-01T12:59:51Z","corr_author":"1","external_id":{"isi":["001547359300001"],"arxiv":["2406.05032"]},"file_date_updated":"2025-10-20T11:02:21Z","date_created":"2025-09-28T22:01:26Z","department":[{"_id":"MaIb"},{"_id":"MiLe"},{"_id":"ZhAl"}],"PlanS_conform":"1","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"acknowledged_ssus":[{"_id":"EM-Fac"}],"issue":"9","_id":"20405","year":"2025","oa_version":"Published Version","title":"Observation of analogue dynamic Schwinger effect and non-perturbative light sensing in lead halide perovskites","article_processing_charge":"Yes (via OA deal)","month":"08","scopus_import":"1","date_published":"2025-08-11T00:00:00Z","abstract":[{"text":"Dielectric breakdown of physical vacuum (Schwinger effect) is the textbook demonstration of compatibility of Relativity and Quantum theory. Although observing this effect is still practically unachievable, its analogue generalizations have been shown to be more readily attainable. This paper demonstrates that a gapped Dirac semiconductor, methylammonium lead-bromide perovskite (MAPbBr3), exhibits analogue dynamic Schwinger effect. Tunneling ionization under deep subgap mid-infrared irradiation leads to intense photoluminescence in the visible range, in full agreement with quasi-adiabatic theory. In addition to revealing a gapped extended system suitable for studying the analogue Schwinger effect, this observation holds great potential for nonperturbative field sensing, i.e., sensing electric fields through nonperturbative light-matter interactions. First, this paper illustrates this by measuring the local deviation from the nominally cubic phase of a perovskite single crystal, which can be interpreted in terms of frozen-in fields. Next, it is shown that analogue dynamic Schwinger effect can be used for nonperturbative amplification of nonparametric upconversion process in perovskites driven simultaneously by multiple optical fields. This discovery demonstrates the potential for material response beyond perturbation theory in the tunneling regime, offering extremely sensitive light detection and amplification across an ultrabroad spectral range not accessible by conventional devices.","lang":"eng"}],"status":"public","OA_type":"hybrid","ddc":["540","530"],"arxiv":1,"acknowledgement":"A.G.V. thanks Peter Balling for useful discussions. This research was supported by the Scientific Service Units (SSU) of ISTA through resources provided by the Electron Microscopy Facility (EMF), and by the Werner Siemens Foundation (WSS) for financial support.","article_type":"original","publication_status":"published","project":[{"_id":"9B8F7476-BA93-11EA-9121-9846C619BF3A","name":"HighTE: The Werner Siemens Laboratory for the High Throughput Discovery of Semiconductors for Waste Heat Recovery"}],"author":[{"full_name":"Lorenc, Dusan","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","first_name":"Dusan","last_name":"Lorenc"},{"last_name":"Volosniev","orcid":"0000-0003-0393-5525","id":"37D278BC-F248-11E8-B48F-1D18A9856A87","full_name":"Volosniev, Artem","first_name":"Artem"},{"first_name":"Ayan A.","full_name":"Zhumekenov, Ayan A.","last_name":"Zhumekenov"},{"id":"BB243B88-D767-11E9-B658-BC13E6697425","full_name":"Lee, Seungho","first_name":"Seungho","orcid":"0000-0002-6962-8598","last_name":"Lee"},{"orcid":"0000-0001-5013-2843","last_name":"Ibáñez","first_name":"Maria","full_name":"Ibáñez, Maria","id":"43C61214-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Osman M.","full_name":"Bakr, Osman M.","last_name":"Bakr"},{"last_name":"Lemeshko","orcid":"0000-0002-6990-7802","first_name":"Mikhail","full_name":"Lemeshko, Mikhail","id":"37CB05FA-F248-11E8-B48F-1D18A9856A87"},{"last_name":"Alpichshev","orcid":"0000-0002-7183-5203","first_name":"Zhanybek","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","full_name":"Alpichshev, Zhanybek"}],"isi":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","file":[{"success":1,"checksum":"d42476279287a9a2f8aeafaef032f4a7","date_updated":"2025-10-20T11:02:21Z","file_name":"2025_ACSPhotonics_Lorenc.pdf","content_type":"application/pdf","access_level":"open_access","creator":"dernst","date_created":"2025-10-20T11:02:21Z","file_id":"20502","relation":"main_file","file_size":6609950}],"oa":1},{"publication":"Physical Review Research","volume":6,"citation":{"short":"D. Lorenc, Z. Alpichshev, Physical Review Research 6 (2024).","ieee":"D. Lorenc and Z. Alpichshev, “Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr effect,” <i>Physical Review Research</i>, vol. 6, no. 1. American Physical Society, 2024.","ista":"Lorenc D, Alpichshev Z. 2024. Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr effect. Physical Review Research. 6(1), 013042.","apa":"Lorenc, D., &#38; Alpichshev, Z. (2024). Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr effect. <i>Physical Review Research</i>. American Physical Society. <a href=\"https://doi.org/10.1103/PhysRevResearch.6.013042\">https://doi.org/10.1103/PhysRevResearch.6.013042</a>","mla":"Lorenc, Dusan, and Zhanybek Alpichshev. “Dispersive Effects in Ultrafast Nonlinear Phenomena: The Case of Optical Kerr Effect.” <i>Physical Review Research</i>, vol. 6, no. 1, 013042, American Physical Society, 2024, doi:<a href=\"https://doi.org/10.1103/PhysRevResearch.6.013042\">10.1103/PhysRevResearch.6.013042</a>.","ama":"Lorenc D, Alpichshev Z. Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr effect. <i>Physical Review Research</i>. 2024;6(1). doi:<a href=\"https://doi.org/10.1103/PhysRevResearch.6.013042\">10.1103/PhysRevResearch.6.013042</a>","chicago":"Lorenc, Dusan, and Zhanybek Alpichshev. “Dispersive Effects in Ultrafast Nonlinear Phenomena: The Case of Optical Kerr Effect.” <i>Physical Review Research</i>. American Physical Society, 2024. <a href=\"https://doi.org/10.1103/PhysRevResearch.6.013042\">https://doi.org/10.1103/PhysRevResearch.6.013042</a>."},"DOAJ_listed":"1","type":"journal_article","publisher":"American Physical Society","day":"11","doi":"10.1103/PhysRevResearch.6.013042","article_number":"013042","department":[{"_id":"ZhAl"}],"file_date_updated":"2024-01-31T11:59:30Z","date_created":"2024-01-28T23:01:42Z","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"publication_identifier":{"eissn":["2643-1564"]},"intvolume":"         6","quality_controlled":"1","language":[{"iso":"eng"}],"corr_author":"1","date_updated":"2025-05-08T10:16:34Z","OA_place":"publisher","has_accepted_license":"1","article_processing_charge":"Yes","month":"01","oa_version":"Published Version","year":"2024","issue":"1","_id":"14886","title":"Dispersive effects in ultrafast nonlinear phenomena: The case of optical Kerr effect","APC_amount":"2982,14 EUR","author":[{"last_name":"Lorenc","full_name":"Lorenc, Dusan","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","first_name":"Dusan"},{"first_name":"Zhanybek","full_name":"Alpichshev, Zhanybek","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-7183-5203","last_name":"Alpichshev"}],"publication_status":"published","article_type":"original","oa":1,"file":[{"file_id":"14918","file_size":2863627,"relation":"main_file","content_type":"application/pdf","creator":"dernst","date_created":"2024-01-31T11:59:30Z","access_level":"open_access","file_name":"2024_PhysicalReviewResearch_Lorenc.pdf","date_updated":"2024-01-31T11:59:30Z","success":1,"checksum":"42d58f93ae74e7f2c4de058ef75ff8b2"}],"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","status":"public","scopus_import":"1","abstract":[{"lang":"eng","text":"It is a basic principle that an effect cannot come before the cause. Dispersive relations that follow from this fundamental fact have proven to be an indispensable tool in physics and engineering. They are most powerful in the domain of linear response where they are known as Kramers-Kronig relations. However, when it comes to nonlinear phenomena the implications of causality are much less explored, apart from several notable exceptions. Here in this paper we demonstrate how to apply the dispersive formalism to analyze the ultrafast nonlinear response in the context of the paradigmatic nonlinear Kerr effect. We find that the requirement of causality introduces a noticeable effect even under assumption that Kerr effect is mediated by quasi-instantaneous off-resonant electronic hyperpolarizability. We confirm this by experimentally measuring the time-resolved Kerr dynamics in GaAs by means of a hybrid pump-probe Mach-Zehnder interferometer and demonstrate the presence of an intrinsic lagging between amplitude and phase responses as predicted by dispersive analysis. Our results describe a general property of the time-resolved nonlinear processes thereby highlighting the importance of accounting for dispersive effects in the nonlinear optical processes involving ultrashort pulses."}],"date_published":"2024-01-11T00:00:00Z","acknowledgement":"The work was supported by the Institute of Science and Technology Austria (ISTA). We thank Prof. John M. Dudley, Dr. Ugur Sezer, and Dr. Artem Volosniev for valuable discussions.","ddc":["530"],"OA_type":"gold"},{"date_created":"2024-09-01T22:01:08Z","article_number":"085403","department":[{"_id":"ZhAl"}],"intvolume":"         8","quality_controlled":"1","language":[{"iso":"eng"}],"publication_identifier":{"eissn":["2475-9953"]},"date_updated":"2025-09-08T09:06:34Z","external_id":{"isi":["001299497800001"]},"corr_author":"1","publication":"Physical Review Materials","citation":{"apa":"Lorenc, D., Zhumekenov, A., Bakr, O. M., &#38; Alpichshev, Z. (2024). No extraordinary χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by means of time-resolved interferometry. <i>Physical Review Materials</i>. American Physical Society. <a href=\"https://doi.org/10.1103/PhysRevMaterials.8.085403\">https://doi.org/10.1103/PhysRevMaterials.8.085403</a>","ista":"Lorenc D, Zhumekenov A, Bakr OM, Alpichshev Z. 2024. No extraordinary χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by means of time-resolved interferometry. Physical Review Materials. 8(8), 085403.","mla":"Lorenc, Dusan, et al. “No Extraordinary χ(3) in Lead-Halide Perovskites: Placing an Upper Bound on Kerr Nonlinearity by Means of Time-Resolved Interferometry.” <i>Physical Review Materials</i>, vol. 8, no. 8, 085403, American Physical Society, 2024, doi:<a href=\"https://doi.org/10.1103/PhysRevMaterials.8.085403\">10.1103/PhysRevMaterials.8.085403</a>.","ieee":"D. Lorenc, A. Zhumekenov, O. M. Bakr, and Z. Alpichshev, “No extraordinary χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by means of time-resolved interferometry,” <i>Physical Review Materials</i>, vol. 8, no. 8. American Physical Society, 2024.","short":"D. Lorenc, A. Zhumekenov, O.M. Bakr, Z. Alpichshev, Physical Review Materials 8 (2024).","chicago":"Lorenc, Dusan, Ayan Zhumekenov, Osman M. Bakr, and Zhanybek Alpichshev. “No Extraordinary χ(3) in Lead-Halide Perovskites: Placing an Upper Bound on Kerr Nonlinearity by Means of Time-Resolved Interferometry.” <i>Physical Review Materials</i>. American Physical Society, 2024. <a href=\"https://doi.org/10.1103/PhysRevMaterials.8.085403\">https://doi.org/10.1103/PhysRevMaterials.8.085403</a>.","ama":"Lorenc D, Zhumekenov A, Bakr OM, Alpichshev Z. No extraordinary χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by means of time-resolved interferometry. <i>Physical Review Materials</i>. 2024;8(8). doi:<a href=\"https://doi.org/10.1103/PhysRevMaterials.8.085403\">10.1103/PhysRevMaterials.8.085403</a>"},"volume":8,"doi":"10.1103/PhysRevMaterials.8.085403","day":"23","publisher":"American Physical Society","type":"journal_article","publication_status":"published","article_type":"original","author":[{"full_name":"Lorenc, Dusan","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","first_name":"Dusan","last_name":"Lorenc"},{"last_name":"Zhumekenov","first_name":"Ayan","full_name":"Zhumekenov, Ayan"},{"first_name":"Osman M.","full_name":"Bakr, Osman M.","last_name":"Bakr"},{"orcid":"0000-0002-7183-5203","last_name":"Alpichshev","first_name":"Zhanybek","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","full_name":"Alpichshev, Zhanybek"}],"user_id":"317138e5-6ab7-11ef-aa6d-ffef3953e345","isi":1,"date_published":"2024-08-23T00:00:00Z","abstract":[{"lang":"eng","text":"Lead halide perovskites have recently been reported to demonstrate an exceptionally high nonlinear (Kerr) refractive index n2 of up to 10−8cm2/W in CH3⁢NH3⁢PbBr3. Other researchers, however, observe different, substantially more conservative numbers. In order to resolve this disagreement, the nonlinear Kerr index of a bulk sample of lead halide perovskite was measured directly by means of an interferometer. This approach has many advantages as compared to the more standard z-scan technique. In particular, this method allows studying the induced changes to the refractive index in a time-resolved manner, thus enabling to separate the different contributions to 𝑛2. The extracted 𝑛2 values for CsPbBr3 and MAPbBr3 at 𝜆≈1µ⁢m are 𝑛2=+2.1×10−14cm2/W and 𝑛2=+6×10−15cm2/W, respectively. Hence, these values are substantially lower than what has been indicated in most of the previous reports, implying the latter one should be regarded with great care."}],"scopus_import":"1","status":"public","acknowledgement":"We gratefully acknowledge the assistance of Prof. John\r\nDudley.","article_processing_charge":"No","month":"08","year":"2024","_id":"17476","issue":"8","oa_version":"None","title":"No extraordinary χ(3) in lead-halide perovskites: Placing an upper bound on Kerr nonlinearity by means of time-resolved interferometry"},{"intvolume":"       123","language":[{"iso":"eng"}],"quality_controlled":"1","publication_identifier":{"issn":["0003-6951"]},"date_updated":"2025-09-09T12:58:23Z","has_accepted_license":"1","external_id":{"isi":["001145465400004"],"arxiv":["2306.09043"]},"corr_author":"1","file_date_updated":"2023-09-20T11:36:16Z","date_created":"2023-09-17T22:01:09Z","article_number":"091104","department":[{"_id":"ZhAl"}],"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"citation":{"ama":"Lorenc D, Alpichshev Z. Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam. <i>Applied Physics Letters</i>. 2023;123(9). doi:<a href=\"https://doi.org/10.1063/5.0161713\">10.1063/5.0161713</a>","chicago":"Lorenc, Dusan, and Zhanybek Alpichshev. “Mid-Infrared Kerr Index Evaluation via Cross-Phase Modulation with a near-Infrared Probe Beam.” <i>Applied Physics Letters</i>. AIP Publishing, 2023. <a href=\"https://doi.org/10.1063/5.0161713\">https://doi.org/10.1063/5.0161713</a>.","short":"D. Lorenc, Z. Alpichshev, Applied Physics Letters 123 (2023).","apa":"Lorenc, D., &#38; Alpichshev, Z. (2023). Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam. <i>Applied Physics Letters</i>. AIP Publishing. <a href=\"https://doi.org/10.1063/5.0161713\">https://doi.org/10.1063/5.0161713</a>","mla":"Lorenc, Dusan, and Zhanybek Alpichshev. “Mid-Infrared Kerr Index Evaluation via Cross-Phase Modulation with a near-Infrared Probe Beam.” <i>Applied Physics Letters</i>, vol. 123, no. 9, 091104, AIP Publishing, 2023, doi:<a href=\"https://doi.org/10.1063/5.0161713\">10.1063/5.0161713</a>.","ista":"Lorenc D, Alpichshev Z. 2023. Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam. Applied Physics Letters. 123(9), 091104.","ieee":"D. Lorenc and Z. Alpichshev, “Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam,” <i>Applied Physics Letters</i>, vol. 123, no. 9. AIP Publishing, 2023."},"volume":123,"publisher":"AIP Publishing","doi":"10.1063/5.0161713","day":"28","type":"journal_article","publication":"Applied Physics Letters","scopus_import":"1","date_published":"2023-08-28T00:00:00Z","abstract":[{"text":"We propose a simple method to measure nonlinear Kerr refractive index in mid-infrared frequency range that avoids using sophisticated infrared detectors. Our approach is based on using a near-infrared probe beam which interacts with a mid-IR beam via wavelength-non-degenerate cross-phase modulation (XPM). By carefully measuring XPM-induced spectral modifications in the probe beam and comparing the experimental data with simulation results, we extract the value for the non-degenerate Kerr index. Finally, in order to obtain the value of degenerate mid-IR Kerr index, we use the well-established two-band formalism of Sheik-Bahae et al., which is shown to become particularly simple in the limit of low frequencies. The proposed technique is complementary to the conventional techniques, such as z-scan, and has the advantage of not requiring any mid-infrared detectors.","lang":"eng"}],"status":"public","acknowledgement":"The work was supported by IST Austria. The authors would like to gratefully acknowledge the help and assistance of Professor John M. Dudley.","ddc":["530"],"arxiv":1,"publication_status":"published","article_type":"original","author":[{"last_name":"Lorenc","first_name":"Dusan","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","full_name":"Lorenc, Dusan"},{"first_name":"Zhanybek","full_name":"Alpichshev, Zhanybek","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","orcid":"0000-0002-7183-5203","last_name":"Alpichshev"}],"file":[{"date_created":"2023-09-20T11:36:16Z","creator":"dernst","access_level":"open_access","content_type":"application/pdf","relation":"main_file","file_size":1486715,"file_id":"14353","checksum":"89a1b604d58b209fec66c6b6f919ac98","success":1,"file_name":"2023_ApplPhysLetter_Lorenc.pdf","date_updated":"2023-09-20T11:36:16Z"}],"isi":1,"user_id":"317138e5-6ab7-11ef-aa6d-ffef3953e345","oa":1,"year":"2023","_id":"14342","issue":"9","oa_version":"Published Version","title":"Mid-infrared Kerr index evaluation via cross-phase modulation with a near-infrared probe beam","article_processing_charge":"Yes (in subscription journal)","month":"08"},{"main_file_link":[{"open_access":"1","url":"https://doi.org/10.48550/arXiv.2203.09443"}],"publication":"Physical Review Letters","day":"10","publisher":"American Physical Society","doi":"10.1103/physrevlett.130.106901","type":"journal_article","citation":{"apa":"Volosniev, A., Shiva Kumar, A., Lorenc, D., Ashourishokri, Y., Zhumekenov, A. A., Bakr, O. M., … Alpichshev, Z. (2023). Spin-electric coupling in lead halide perovskites. <i>Physical Review Letters</i>. American Physical Society. <a href=\"https://doi.org/10.1103/physrevlett.130.106901\">https://doi.org/10.1103/physrevlett.130.106901</a>","ista":"Volosniev A, Shiva Kumar A, Lorenc D, Ashourishokri Y, Zhumekenov AA, Bakr OM, Lemeshko M, Alpichshev Z. 2023. Spin-electric coupling in lead halide perovskites. Physical Review Letters. 130(10), 106901.","mla":"Volosniev, Artem, et al. “Spin-Electric Coupling in Lead Halide Perovskites.” <i>Physical Review Letters</i>, vol. 130, no. 10, 106901, American Physical Society, 2023, doi:<a href=\"https://doi.org/10.1103/physrevlett.130.106901\">10.1103/physrevlett.130.106901</a>.","ieee":"A. Volosniev <i>et al.</i>, “Spin-electric coupling in lead halide perovskites,” <i>Physical Review Letters</i>, vol. 130, no. 10. American Physical Society, 2023.","short":"A. Volosniev, A. Shiva Kumar, D. Lorenc, Y. Ashourishokri, A.A. Zhumekenov, O.M. Bakr, M. Lemeshko, Z. Alpichshev, Physical Review Letters 130 (2023).","chicago":"Volosniev, Artem, Abhishek Shiva Kumar, Dusan Lorenc, Younes Ashourishokri, Ayan A. Zhumekenov, Osman M. Bakr, Mikhail Lemeshko, and Zhanybek Alpichshev. “Spin-Electric Coupling in Lead Halide Perovskites.” <i>Physical Review Letters</i>. American Physical Society, 2023. <a href=\"https://doi.org/10.1103/physrevlett.130.106901\">https://doi.org/10.1103/physrevlett.130.106901</a>.","ama":"Volosniev A, Shiva Kumar A, Lorenc D, et al. Spin-electric coupling in lead halide perovskites. <i>Physical Review Letters</i>. 2023;130(10). doi:<a href=\"https://doi.org/10.1103/physrevlett.130.106901\">10.1103/physrevlett.130.106901</a>"},"volume":130,"date_created":"2023-03-14T13:11:59Z","department":[{"_id":"GradSch"},{"_id":"ZhAl"},{"_id":"MiLe"}],"article_number":"106901","date_updated":"2025-04-23T08:53:33Z","corr_author":"1","external_id":{"arxiv":["2203.09443"],"isi":["000982435900002"],"pmid":["36962044"]},"language":[{"iso":"eng"}],"quality_controlled":"1","intvolume":"       130","publication_identifier":{"eissn":["1079-7114"],"issn":["0031-9007"]},"pmid":1,"month":"03","article_processing_charge":"No","keyword":["General Physics and Astronomy"],"title":"Spin-electric coupling in lead halide perovskites","issue":"10","_id":"12723","year":"2023","oa_version":"Preprint","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","isi":1,"oa":1,"article_type":"original","publication_status":"published","author":[{"orcid":"0000-0003-0393-5525","last_name":"Volosniev","first_name":"Artem","id":"37D278BC-F248-11E8-B48F-1D18A9856A87","full_name":"Volosniev, Artem"},{"last_name":"Shiva Kumar","first_name":"Abhishek","id":"5e9a6931-eb97-11eb-a6c2-e96f7058d77a","full_name":"Shiva Kumar, Abhishek"},{"last_name":"Lorenc","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","full_name":"Lorenc, Dusan","first_name":"Dusan"},{"first_name":"Younes","full_name":"Ashourishokri, Younes","id":"e32c111f-f6e0-11ea-865d-eb955baea334","last_name":"Ashourishokri"},{"last_name":"Zhumekenov","first_name":"Ayan A.","full_name":"Zhumekenov, Ayan A."},{"full_name":"Bakr, Osman M.","first_name":"Osman M.","last_name":"Bakr"},{"full_name":"Lemeshko, Mikhail","id":"37CB05FA-F248-11E8-B48F-1D18A9856A87","first_name":"Mikhail","orcid":"0000-0002-6990-7802","last_name":"Lemeshko"},{"id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","full_name":"Alpichshev, Zhanybek","first_name":"Zhanybek","orcid":"0000-0002-7183-5203","last_name":"Alpichshev"}],"arxiv":1,"abstract":[{"text":"Lead halide perovskites enjoy a number of remarkable optoelectronic properties. To explain their origin, it is necessary to study how electromagnetic fields interact with these systems. We address this problem here by studying two classical quantities: Faraday rotation and the complex refractive index in a paradigmatic perovskite CH3NH3PbBr3 in a broad wavelength range. We find that the minimal coupling of electromagnetic fields to the k⋅p Hamiltonian is insufficient to describe the observed data even on the qualitative level. To amend this, we demonstrate that there exists a relevant atomic-level coupling between electromagnetic fields and the spin degree of freedom. This spin-electric coupling allows for quantitative description of a number of previous as well as present experimental data. In particular, we use it here to show that the Faraday effect in lead halide perovskites is dominated by the Zeeman splitting of the energy levels and has a substantial beyond-Becquerel contribution. Finally, we present general symmetry-based phenomenological arguments that in the low-energy limit our effective model includes all basis coupling terms to the electromagnetic field in the linear order.","lang":"eng"}],"scopus_import":"1","date_published":"2023-03-10T00:00:00Z","status":"public"},{"oa":1,"user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","isi":1,"author":[{"last_name":"Volosniev","orcid":"0000-0003-0393-5525","full_name":"Volosniev, Artem","id":"37D278BC-F248-11E8-B48F-1D18A9856A87","first_name":"Artem"},{"first_name":"Abhishek","full_name":"Shiva Kumar, Abhishek","id":"5e9a6931-eb97-11eb-a6c2-e96f7058d77a","last_name":"Shiva Kumar"},{"last_name":"Lorenc","first_name":"Dusan","full_name":"Lorenc, Dusan","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87"},{"first_name":"Younes","full_name":"Ashourishokri, Younes","id":"e32c111f-f6e0-11ea-865d-eb955baea334","last_name":"Ashourishokri"},{"first_name":"Ayan","full_name":"Zhumekenov, Ayan","last_name":"Zhumekenov"},{"last_name":"Bakr","full_name":"Bakr, Osman M.","first_name":"Osman M."},{"last_name":"Lemeshko","orcid":"0000-0002-6990-7802","id":"37CB05FA-F248-11E8-B48F-1D18A9856A87","full_name":"Lemeshko, Mikhail","first_name":"Mikhail"},{"last_name":"Alpichshev","orcid":"0000-0002-7183-5203","full_name":"Alpichshev, Zhanybek","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","first_name":"Zhanybek"}],"article_type":"original","publication_status":"published","arxiv":1,"status":"public","date_published":"2023-03-15T00:00:00Z","scopus_import":"1","abstract":[{"lang":"eng","text":"We use general symmetry-based arguments to construct an effective model suitable for studying optical properties of lead halide perovskites. To build the model, we identify an atomic-level interaction between electromagnetic fields and the spin degree of freedom that should be added to a minimally coupled k⋅p Hamiltonian. As a first application, we study two basic optical characteristics of the material: the Verdet constant and the refractive index. Beyond these linear characteristics of the material, the model is suitable for calculating nonlinear effects such as the third-order optical susceptibility. Analysis of this quantity shows that the geometrical properties of the spin-electric term imply isotropic optical response of the system, and that optical anisotropy of lead halide perovskites is a manifestation of hopping of charge carriers. To illustrate this, we discuss third-harmonic generation."}],"month":"03","article_processing_charge":"No","title":"Effective model for studying optical properties of lead halide perovskites","oa_version":"Preprint","_id":"12724","issue":"12","year":"2023","department":[{"_id":"GradSch"},{"_id":"ZhAl"},{"_id":"MiLe"}],"article_number":"125201","date_created":"2023-03-14T13:13:05Z","corr_author":"1","external_id":{"arxiv":["2204.04022"],"isi":["000972602200006"]},"date_updated":"2024-10-09T21:04:46Z","publication_identifier":{"issn":["2469-9950"],"eissn":["2469-9969"]},"quality_controlled":"1","language":[{"iso":"eng"}],"intvolume":"       107","main_file_link":[{"url":"https://doi.org/10.48550/arXiv.2204.04022","open_access":"1"}],"publication":"Physical Review B","type":"journal_article","day":"15","publisher":"American Physical Society","doi":"10.1103/physrevb.107.125201","volume":107,"citation":{"chicago":"Volosniev, Artem, Abhishek Shiva Kumar, Dusan Lorenc, Younes Ashourishokri, Ayan Zhumekenov, Osman M. Bakr, Mikhail Lemeshko, and Zhanybek Alpichshev. “Effective Model for Studying Optical Properties of Lead Halide Perovskites.” <i>Physical Review B</i>. American Physical Society, 2023. <a href=\"https://doi.org/10.1103/physrevb.107.125201\">https://doi.org/10.1103/physrevb.107.125201</a>.","ama":"Volosniev A, Shiva Kumar A, Lorenc D, et al. Effective model for studying optical properties of lead halide perovskites. <i>Physical Review B</i>. 2023;107(12). doi:<a href=\"https://doi.org/10.1103/physrevb.107.125201\">10.1103/physrevb.107.125201</a>","ista":"Volosniev A, Shiva Kumar A, Lorenc D, Ashourishokri Y, Zhumekenov A, Bakr OM, Lemeshko M, Alpichshev Z. 2023. Effective model for studying optical properties of lead halide perovskites. Physical Review B. 107(12), 125201.","mla":"Volosniev, Artem, et al. “Effective Model for Studying Optical Properties of Lead Halide Perovskites.” <i>Physical Review B</i>, vol. 107, no. 12, 125201, American Physical Society, 2023, doi:<a href=\"https://doi.org/10.1103/physrevb.107.125201\">10.1103/physrevb.107.125201</a>.","apa":"Volosniev, A., Shiva Kumar, A., Lorenc, D., Ashourishokri, Y., Zhumekenov, A., Bakr, O. M., … Alpichshev, Z. (2023). Effective model for studying optical properties of lead halide perovskites. <i>Physical Review B</i>. American Physical Society. <a href=\"https://doi.org/10.1103/physrevb.107.125201\">https://doi.org/10.1103/physrevb.107.125201</a>","ieee":"A. Volosniev <i>et al.</i>, “Effective model for studying optical properties of lead halide perovskites,” <i>Physical Review B</i>, vol. 107, no. 12. American Physical Society, 2023.","short":"A. Volosniev, A. Shiva Kumar, D. Lorenc, Y. Ashourishokri, A. Zhumekenov, O.M. Bakr, M. Lemeshko, Z. Alpichshev, Physical Review B 107 (2023)."}},{"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","image":"/images/cc_by.png","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","short":"CC BY (4.0)"},"date_created":"2023-07-18T11:13:17Z","file_date_updated":"2023-07-19T06:55:39Z","department":[{"_id":"MiLe"},{"_id":"ZhAl"}],"has_accepted_license":"1","date_updated":"2025-04-23T13:01:50Z","corr_author":"1","external_id":{"arxiv":["2304.14198"],"isi":["001022811500001"],"pmid":["37405449"]},"quality_controlled":"1","language":[{"iso":"eng"}],"intvolume":"        14","publication_identifier":{"eissn":["1948-7185"]},"publication":"The Journal of Physical Chemistry Letters","day":"05","doi":"10.1021/acs.jpclett.3c01158","publisher":"American Chemical Society","page":"6309-6314","ec_funded":1,"type":"journal_article","citation":{"chicago":"Wei, Yujing, Artem Volosniev, Dusan Lorenc, Ayan A. Zhumekenov, Osman M. Bakr, Mikhail Lemeshko, and Zhanybek Alpichshev. “Bond Polarizability as a Probe of Local Crystal Fields in Hybrid Lead-Halide Perovskites.” <i>The Journal of Physical Chemistry Letters</i>. American Chemical Society, 2023. <a href=\"https://doi.org/10.1021/acs.jpclett.3c01158\">https://doi.org/10.1021/acs.jpclett.3c01158</a>.","ama":"Wei Y, Volosniev A, Lorenc D, et al. Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites. <i>The Journal of Physical Chemistry Letters</i>. 2023;14(27):6309-6314. doi:<a href=\"https://doi.org/10.1021/acs.jpclett.3c01158\">10.1021/acs.jpclett.3c01158</a>","apa":"Wei, Y., Volosniev, A., Lorenc, D., Zhumekenov, A. A., Bakr, O. M., Lemeshko, M., &#38; Alpichshev, Z. (2023). Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites. <i>The Journal of Physical Chemistry Letters</i>. American Chemical Society. <a href=\"https://doi.org/10.1021/acs.jpclett.3c01158\">https://doi.org/10.1021/acs.jpclett.3c01158</a>","ista":"Wei Y, Volosniev A, Lorenc D, Zhumekenov AA, Bakr OM, Lemeshko M, Alpichshev Z. 2023. Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites. The Journal of Physical Chemistry Letters. 14(27), 6309–6314.","mla":"Wei, Yujing, et al. “Bond Polarizability as a Probe of Local Crystal Fields in Hybrid Lead-Halide Perovskites.” <i>The Journal of Physical Chemistry Letters</i>, vol. 14, no. 27, American Chemical Society, 2023, pp. 6309–14, doi:<a href=\"https://doi.org/10.1021/acs.jpclett.3c01158\">10.1021/acs.jpclett.3c01158</a>.","ieee":"Y. Wei <i>et al.</i>, “Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites,” <i>The Journal of Physical Chemistry Letters</i>, vol. 14, no. 27. American Chemical Society, pp. 6309–6314, 2023.","short":"Y. Wei, A. Volosniev, D. Lorenc, A.A. Zhumekenov, O.M. Bakr, M. Lemeshko, Z. Alpichshev, The Journal of Physical Chemistry Letters 14 (2023) 6309–6314."},"volume":14,"isi":1,"user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","file":[{"file_id":"13253","relation":"main_file","file_size":2121252,"content_type":"application/pdf","date_created":"2023-07-19T06:55:39Z","creator":"dernst","access_level":"open_access","file_name":"2023_JourPhysChemistry_Wei.pdf","date_updated":"2023-07-19T06:55:39Z","success":1,"checksum":"c0c040063f06a51b9c463adc504f1a23"}],"oa":1,"publication_status":"published","article_type":"original","project":[{"name":"Angulon: physics and applications of a new quasiparticle","call_identifier":"H2020","grant_number":"801770","_id":"2688CF98-B435-11E9-9278-68D0E5697425"}],"author":[{"last_name":"Wei","orcid":"0000-0001-8913-9719","first_name":"Yujing","id":"0c5ff007-2600-11ee-b896-98bd8d663294","full_name":"Wei, Yujing"},{"last_name":"Volosniev","orcid":"0000-0003-0393-5525","full_name":"Volosniev, Artem","id":"37D278BC-F248-11E8-B48F-1D18A9856A87","first_name":"Artem"},{"first_name":"Dusan","id":"40D8A3E6-F248-11E8-B48F-1D18A9856A87","full_name":"Lorenc, Dusan","last_name":"Lorenc"},{"last_name":"Zhumekenov","first_name":"Ayan A.","full_name":"Zhumekenov, Ayan A."},{"last_name":"Bakr","first_name":"Osman M.","full_name":"Bakr, Osman M."},{"first_name":"Mikhail","id":"37CB05FA-F248-11E8-B48F-1D18A9856A87","full_name":"Lemeshko, Mikhail","last_name":"Lemeshko","orcid":"0000-0002-6990-7802"},{"orcid":"0000-0002-7183-5203","last_name":"Alpichshev","id":"45E67A2A-F248-11E8-B48F-1D18A9856A87","full_name":"Alpichshev, Zhanybek","first_name":"Zhanybek"}],"ddc":["530"],"arxiv":1,"acknowledgement":"We thank Bingqing Cheng and Hong-Zhou Ye for valuable discussions; Y.W.’s work at IST Austria was supported through ISTernship summer internship program funded by OeADGmbH; D.L. and Z.A. acknowledge support by IST Austria (ISTA); M.L. acknowledges support by the European Research Council (ERC) Starting Grant No. 801770 (ANGULON).\r\nA.A.Z. and O.M.B. acknowledge support by KAUST.","date_published":"2023-07-05T00:00:00Z","scopus_import":"1","abstract":[{"text":"A rotating organic cation and a dynamically disordered soft inorganic cage are the hallmark features of organic-inorganic lead-halide perovskites. Understanding the interplay between these two subsystems is a challenging problem, but it is this coupling that is widely conjectured to be responsible for the unique behavior of photocarriers in these materials. In this work, we use the fact that the polarizability of the organic cation strongly depends on the ambient electrostatic environment to put the molecule forward as a sensitive probe of the local crystal fields inside the lattice cell. We measure the average polarizability of the C/N–H bond stretching mode by means of infrared spectroscopy, which allows us to deduce the character of the motion of the cation molecule, find the magnitude of the local crystal field, and place an estimate on the strength of the hydrogen bond between the hydrogen and halide atoms. Our results pave the way for understanding electric fields in lead-halide perovskites using infrared bond spectroscopy.","lang":"eng"}],"status":"public","pmid":1,"month":"07","article_processing_charge":"Yes (via OA deal)","keyword":["General Materials Science","Physical and Theoretical Chemistry"],"title":"Bond polarizability as a probe of local crystal fields in hybrid lead-halide perovskites","issue":"27","_id":"13251","year":"2023","oa_version":"Published Version"}]