Bilayer graphene. Tunable fractional quantum Hall phases in bilayer graphene

Patrick Maher; Lei Wang; Yuanda Gao; Carlos Forsythe; Takashi Taniguchi; Kenji Watanabe; Dmitry Abanin; Zlatko Papić; Paul Cadden-Zimansky; James Hone; Philip Kim; Cory R Dean

doi:10.1126/science.1252875

Bilayer graphene. Tunable fractional quantum Hall phases in bilayer graphene

Science. 2014 Jul 4;345(6192):61-4. doi: 10.1126/science.1252875.

Authors

Affiliations

¹ Department of Physics, Columbia University, New York, NY 10027, USA.
² Department of Electrical Engineering, Columbia University, New York, NY 10027, USA.
³ Department of Mechanical Engineering, Columbia University, New York, NY 10027, USA.
⁴ National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan.
⁵ Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5, Canada. Institute for Quantum Computing, Waterloo, ON N2L 3G1, Canada.
⁶ Physics Program, Bard College, Annandale-on-Hudson, NY 12504, USA.
⁷ Department of Physics, Columbia University, New York, NY 10027, USA. [email protected] [email protected].
⁸ Department of Physics, The City College of New York, New York, NY 10031, USA. [email protected] [email protected].

PMID: 24994646
DOI: 10.1126/science.1252875

Abstract

Symmetry-breaking in a quantum system often leads to complex emergent behavior. In bilayer graphene (BLG), an electric field applied perpendicular to the basal plane breaks the inversion symmetry of the lattice, opening a band gap at the charge neutrality point. In a quantizing magnetic field, electron interactions can cause spontaneous symmetry-breaking within the spin and valley degrees of freedom, resulting in quantum Hall effect (QHE) states with complex order. Here, we report fractional QHE states in BLG that show phase transitions that can be tuned by a transverse electric field. This result provides a model platform with which to study the role of symmetry-breaking in emergent states with topological order.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.