Hubmann, S. and Soul, P. and Di Battista, G. and Hild, M. and Watanabe, K. and Taniguchi, T. and Efetov, D. K. and Ganichev, S. D. (2022) Nonlinear intensity dependence of photogalvanics and photoconductance induced by terahertz laser radiation in twisted bilayer graphene close to magic angle. PHYSICAL REVIEW MATERIALS, 6 (2): 024003. ISSN 2475-9953
Full text not available from this repository.Abstract
We report on the observation of the nonlinear intensity dependence of the bulk photogalvanic current and photoconductivity in the twisted graphene with small twist angles close to the second magic angle. We show that terahertz radiation results in photoresponses, which are caused by indirect optical transitions (free carrier absorption), direct interband transitions, and optical transitions between moire subbands. The relative contribution of these absorption channels depends on the Fermi-level position with respect to the multiple moire subbands of the twisted graphene. The interplay of these absorption channels results in oscillations of the photoresponses with variation of the gate voltage. We show that the photoresponse saturates at high intensities. For different absorption channels it has different intensity dependencies and saturation intensities. The latter depends nonmonotonically on the Fermi-level position, which is controlled by the gate voltage.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CORRELATED STATES; MOIRE BANDS; SUPERCONDUCTIVITY; ELECTRONICS |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Professor Ganichev > Group Sergey Ganichev |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 15 Feb 2024 11:53 |
| Last Modified: | 15 Feb 2024 11:53 |
| URI: | https://pred.uni-regensburg.de/id/eprint/57627 |
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