Observation of the Spin-Orbit Gap in Bilayer Graphene by One-Dimensional Ballistic Transport
Abstract
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 μ eV 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 6 e2/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.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 2020
- DOI:
- 10.1103/PhysRevLett.124.177701
- arXiv:
- arXiv:1911.13176
- Bibcode:
- 2020PhRvL.124q7701B
- Keywords:
-
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 5 pages, 4 figures, Supplement 6 figures