Masia, Francesco  ORCID: https://orcid.org/0000-0003-4958-410X, Langbein, Wolfgang Werner ORCID: https://orcid.org/0000-0001-9786-1023, Moreels, Iwan, Hens, Zeger and Borri, Paola ORCID: https://orcid.org/0000-0002-7873-3314
2011.
Exciton dephasing in lead sulfide quantum dots by X-point phonons.
Physical Review B
83
(20)
, 201309.
10.1103/PhysRevB.83.201309
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Abstract
Using a sensitive transient four-wave mixing technique in heterodyne detection, we measured the ground-state excitonic dephasing in PbS colloidal quantum dots of 4–6-nm diameter in the temperature range from 5 to 100 K. We observe an ultrafast (<100 fs) initial decay followed by a component of about 300 fs at 5 K, which becomes faster with decreasing dot size and increasing temperature. This dynamics is attributed to pure dephasing of phonon-assisted transitions in the peculiar band structure of PbS, which allows coupling to phonons with wave vectors both near the Brillouin zone center and near the (100) zone edge, the X point. We estimate an upper limit of 7% for the weight of the zero-phonon line with 2.6-ps spin-flip limited dephasing.
| Item Type: | Article |
|---|---|
| Date Type: | Publication |
| Status: | Published |
| Schools: | Schools > Biosciences Schools > Physics and Astronomy |
| Subjects: | Q Science > Q Science (General) Q Science > QC Physics |
| Additional Information: | 4 pp. |
| Publisher: | American Physical Society |
| ISSN: | 1098-0121 |
| Funders: | EPSRC |
| Last Modified: | 15 May 2023 23:28 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/22819 |
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