title: Helical edge states and fractional quantum Hall effect in a graphene electron-hole bilayer.
abstract: Helical 1D electronic systems are a promising route towards realizing circuits of topological quantum states that exhibit non-Abelian statistics. Here, we demonstrate a versatile platform to realize 1D systems made by combining quantum Hall (QH) edge states of opposite chiralities in a graphene electron-hole bilayer at moderate magnetic fields. Using this approach, we engineer helical 1D edge conductors where the counterpropagating modes are localized in separate electron and hole layers by a tunable electric field. These helical conductors exhibit strong non-local transport signals and suppressed backscattering due to the opposite spin polarizations of the counterpropagating modes. Unlike other approaches used for realizing helical states, the graphene electron-hole bilayer can be used to build new 1D systems incorporating fractional edge states. Indeed, we are able to tune the bilayer devices into a regime hosting fractional and integer edge states of opposite chiralities, paving the way towards 1D helical conductors with fractional quantum statistics.
authors: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors: Javier D
authors: JD
authors: Sanchez-Yamagishi
authors: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors: Jason Y
authors: 0000-0002-3189-6984
authors: JY
authors: Luo
authors: Department of Physics, University of California Santa Barbara, Santa Barbara, California 93106, USA.
authors: Andrea F
authors: AF
authors: Young
authors: Department of Physics, Carnegie Mellon University, Pittsburg, Pennsylvania 15213, USA.
authors: Benjamin M
authors: BM
authors: Hunt
authors: Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
authors: Kenji
authors: 0000-0003-3701-8119
authors: K
authors: Watanabe
authors: Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
authors: Takashi
authors: T
authors: Taniguchi
authors: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors: Raymond C
authors: RC
authors: Ashoori
authors: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors: Pablo
authors: P
authors: Jarillo-Herrero