Bray, C. and Maussang, K. and Consejo, C. and Delgado-Notario, J. A. and Krishtopenko, S. and Gebert, S. and Yahniuk, I. and Ruffenach, S. and Dinar, K. and Eroms, J. and Indykiewicz, K. and Jouault, B. and Torres, J. and Meziani, Y. M. and Knap, W. and Yurgens, A. and Ganichev, S. D. and Teppe, F. (2022) Temperature-dependent zero-field splittings in graphene. PHYSICAL REVIEW B, 106 (24): 245141. ISSN 2469-9950, 2469-9969
Full text not available from this repository. (Request a copy)Abstract
Graphene is a quantum spin Hall insulator with a 45 mu eV-wide nontrivial topological gap induced by the intrinsic spin-orbit coupling. Even though this zero-field spin splitting is weak, it makes graphene an attractive candidate for applications in quantum technologies, given the resulting long spin-relaxation time. On the other side, the staggered sublattice potential, resulting from the coupling of graphene with its boron nitride substrate, compensates intrinsic spin-orbit coupling and decreases the nontrivial topological gap, which may lead to the phase transition into trivial band insulator state. In this work, we present extensive experimental studies of the zero-field splittings in monolayer and bilayer graphene in a temperature range 2-12 K by means of subterahertz photoconductivity-based electron spin-resonance technique. Surprisingly, we observe a decrease of the spin splittings with increasing temperature. We discuss the origin of this phenomenon by considering possible physical mechanisms likely to induce a temperature dependence of the spin-orbit coupling. These include the difference in the expansion coefficients between the graphene and the boron nitride substrate or the metal contacts, the electron-phonon interactions, and the presence of a magnetic order at low temperature. Our experimental observation expands knowledge about the nontrivial topological gap in graphene.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | THERMAL-EXPANSION COEFFICIENT; ELECTRON-SPIN-RESONANCE; TERAHERTZ DETECTION; PERFORMANCE |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Professor Ganichev > Group Sergey Ganichev Physics > Institute of Experimental and Applied Physics > Chair Professor Weiss > Group Jonathan Eroms |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 20 Feb 2024 08:51 |
| Last Modified: | 20 Feb 2024 08:51 |
| URI: | https://pred.uni-regensburg.de/id/eprint/58306 |
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