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L. Banszerus, F. Frohn, T. Fabian, S. Somanchi, A. Epping, M. Müller, D. Neumaier, K. Watanabe, T. Taniguchi, F. Libisch, B. Beschoten, F. Hassler, C Stampfer:
"Observation of the spin-orbit gap in bilayer graphene by one-dimensional ballistic transport";
Physical Review Letters, 124 (2020), 177701 - 177705.

We report on measurements of quantized conductance in gate-defined quantum point contacts in bilayer graphene that allow the observation of subband splittings due to spin-orbit coupling. The size of this splitting can be tuned from 40 to 80  μeV by the displacement field. We assign this gate-tunable subband splitting to a gap induced by spin-orbit coupling of Kane-Mele type, enhanced by proximity effects due to the substrate. We show that this spin-orbit coupling gives rise to a complex pattern in low perpendicular magnetic fields, increasing the Zeeman splitting in one valley and suppressing it in the other one. In addition, we observe a spin polarized channel of 6e2/h at high in-plane magnetic field and signatures of interaction effects at the crossings of spin-split subbands of opposite spins at finite magnetic field.

Graphene, Bilayer Graphene, Quantum transport

http://dx.doi.org/10.1103/PhysRevLett.124.177701

https://publik.tuwien.ac.at/files/publik_292446.pdf