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Optical observation of superconducting density of states in luminescence spectra of InAs quantum dots
| Title: | Optical observation of superconducting density of states in luminescence spectra of InAs quantum dots |
| Authors: | Mou, S. S. Browse this author | | Irie, H. Browse this author | | Asano, Y. Browse this author →KAKEN DB | | Akahane, K. Browse this author | | Nakajima, H. Browse this author | | Kumano, H. Browse this author →KAKEN DB | | Sasaki, M. Browse this author | | Murayama, A. Browse this author | | Suemune, I. Browse this author →KAKEN DB |
| Issue Date: | 15-Jul-2015 |
| Publisher: | American Physical Society |
| Journal Title: | Physical review B |
| Volume: | 92 |
| Issue: | 3 |
| Start Page: | 035308-1 |
| End Page: | 035308-9 |
| Publisher DOI: | 10.1103/PhysRevB.92.035308 |
| Abstract: | We study luminescence spectra observed from InAs quantum dots (QDs) embedded in an n-type InGaAs-based heterostructure, where electron Cooper pairs penetrate from an adjacent niobium (Nb) superconductor with the proximity effect. Below the superconducting (SC) critical temperature of Nb, we observe substantial luminescence intensity enhancement and a sharp edge in luminescence spectra of InAs QDs. We explain the observed sharp edge in the luminescence spectra with the proximity effect, that is, with the consideration of opening of SC gap and modification of density of states (DOS) near the electron Fermi level in the n-type semiconductor heterostructure. We demonstrate that the sharp edge luminescence spectra are well reproduced by the SC DOS, with quasiparticle lifetime broadening and a Gaussian distribution of lowest QD state emission lines. We discuss the reason why it has been difficult to observe the sharp edge luminescence spectra in the previous quantum well-based SC light emitting diodes. |
| Rights: | ©2015 American Physical Society |
| Type: | article |
| URI: | http://hdl.handle.net/2115/59814 |
| Appears in Collections: | 電子科学研究所 (Research Institute for Electronic Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 末宗 幾夫
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