Temperature dependance of Intrinsic Spin Orbit Coupling Gap in Graphene probed by Terahertz photoconductivity

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.

Dinar, K.Laboratoire Charles Coulomb (författare)
Bray, C.Laboratoire Charles Coulomb (författare)
Consejo, C.Laboratoire Charles Coulomb (författare)
Delgado-Notario, J. A.Polish Academy of Sciences,Universidad de Salamanca,University of Salamanca (författare)
Krishtopenko, S.Laboratoire Charles Coulomb (författare)
Yahniuk, I.Universität Regensburg,University of Regensburg,Polish Academy of Sciences (författare)
Gerbert, S.Laboratoire Charles Coulomb (författare)
Ruffenach, S.Laboratoire Charles Coulomb (författare)
Moench, E.Universität Regensburg,University of Regensburg (författare)
Indykiewicz, KorneliaPolitechnika Wrocławska,Wrocław University of Science and Technology (författare)
Benhamoumbui, B.Laboratoire Charles Coulomb (författare)
Jouault, B.Laboratoire Charles Coulomb (författare)
Torres, J. (författare)
Meziani, Y. M.Universidad de Salamanca,University of Salamanca (författare)
Knap, W.Laboratoire Charles Coulomb (författare)
Yurgens, Avgust,1959Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)yurgens (författare)
Ganichev, S.D.Universität Regensburg,University of Regensburg,Polish Academy of Sciences (författare)
Teppe, F.Laboratoire Charles Coulomb (författare)
Laboratoire Charles CoulombPolish Academy of Sciences (creator_code:org_t)

Ingår i:International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz2162-20272162-2035

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