Temperature dependance of Intrinsic Spin Orbit Coupling Gap in Graphene probed by Terahertz photoconductivity
Paper in proceeding, 2023
Graphene is a quantum spin Hall insulator, with a nontrivial topological gap induced by the spin-orbit coupling. Such splitting is weak (∼ 45 μ eV) in the absence of external magnetic field. However, due to rather long spin-relaxation time, graphene is an attractive candidate for applications in quantum technologies. When it is encapsulated in hexagonal boron nitride, the coupling between graphene and the substrate compensates intrinsic spin-orbit coupling and decreases the nontrivial topological gap, which may lead to phase transition into a trivial band insulator state. In this work, we have measured experimentally the zero-field splittings in monolayer and bilayer graphene by the means of subterahertz photoconductivity-based electron spin resonance technique. The dependance in temperature of such splittings have been also studied in the 2-12K range. We observed a decrease of the spin splittings with increasing temperature. Such behavior might be understood from several physical mechanisms that could induce a temperature dependence of the spin-orbit coupling. These includes the difference in the expansion coefficients between the graphene and the boron nitride substrate or the metal contacts, the electronphonon interactions, and the presence of a magnetic order at low temperature.
Author
K. Maussang
IES Institut d'Electronique et des Systèmes
K. Dinar
Laboratoire Charles Coulomb
C. Bray
Laboratoire Charles Coulomb
C. Consejo
Laboratoire Charles Coulomb
J. A. Delgado-Notario
Polish Academy of Sciences
University of Salamanca
S. Krishtopenko
Laboratoire Charles Coulomb
I. Yahniuk
University of Regensburg
Polish Academy of Sciences
S. Gerbert
IES Institut d'Electronique et des Systèmes
Laboratoire Charles Coulomb
S. Ruffenach
Laboratoire Charles Coulomb
E. Moench
University of Regensburg
Kornelia Indykiewicz
Wrocław University of Science and Technology
B. Benhamoumbui
Laboratoire Charles Coulomb
B. Jouault
Laboratoire Charles Coulomb
J. Torres
IES Institut d'Electronique et des Systèmes
Y. M. Meziani
University of Salamanca
W. Knap
Laboratoire Charles Coulomb
Avgust Yurgens
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
S.D. Ganichev
University of Regensburg
Polish Academy of Sciences
F. Teppe
Laboratoire Charles Coulomb
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz
21622027 (ISSN) 21622035 (eISSN)
9798350336603 (ISBN)
48th International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz 2023
Montreal, Canada,
Montreal, Canada,
Subject Categories
Condensed Matter Physics
DOI
10.1109/IRMMW-THz57677.2023.10299006