Tunable Symmetries of Integer and Fractional Quantum Hall Phases in Heterostructures with Multiple Dirac Bands

Petr Stepanov, Yafis Barlas, Tim Espiritu, Shi Che, Kenji Watanabe, Takashi Taniguchi, Dmitry Smirnov, and Chun Ning Lau

Phys. Rev. Lett. 117, 076807 – Published 12 August 2016

Abstract

The copresence of multiple Dirac bands in few-layer graphene leads to a rich phase diagram in the quantum Hall regime. Using transport measurements, we map the phase diagram of BN-encapsulated $A B A$ -stacked trilayer graphene as a function charge density $n$ , magnetic field $B$ , and interlayer displacement field $D$ , and observe transitions among states with different spin, valley, orbital, and parity polarizations. Such a rich pattern arises from crossings between Landau levels from different subbands, which reflect the evolving symmetries that are tunable in situ. At $D = 0$ , we observe fractional quantum Hall (FQH) states at filling factors $2 / 3$ and $- 11 / 3$ . Unlike those in bilayer graphene, these FQH states are destabilized by a small interlayer potential that hybridizes the different Dirac bands.

Received 5 May 2016

DOI:https://doi.org/10.1103/PhysRevLett.117.076807

Physics Subject Headings (PhySH)

Magnetotransport Quantum Hall effect

2-dimensional systems Graphene Heterostructures

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Petr Stepanov¹, Yafis Barlas¹, Tim Espiritu¹, Shi Che¹, Kenji Watanabe², Takashi Taniguchi², Dmitry Smirnov³, and Chun Ning Lau^1,*

¹Department of Physics and Astronomy, University of California, Riverside, Riverside, California 92521, USA
²National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
³National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA