Ballistic miniband conduction in a graphene superlattice
Abstract
Rational design of long-period artificial lattices yields effects unavailable in simple solids. The moiré pattern in highly aligned graphene/hexagonal boron nitride (h-BN) heterostructures is a lateral superlattice with high electron mobility and an unusual electronic dispersion whose miniband edges and saddle points can be reached by electrostatic gating. We investigated the dynamics of electrons in moiré minibands by measuring ballistic transport between adjacent local contacts in a magnetic field, known as the transverse electron focusing effect. At low temperatures, we observed caustics of skipping orbits extending over hundreds of superlattice periods, reversals of the cyclotron revolution for successive minibands, and breakdown of cyclotron motion near van Hove singularities. At high temperatures, electron-electron collisions suppress focusing. Probing such miniband conduction properties is a necessity for engineering novel transport behaviors in superlattice devices.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 30, 2016
- Source ID
- 10.1126/science.aaf1095
Entities
People
- David Goldhaber-Gordon
- John R. Wallbank
- Kenji Watanabe
- Menyoung Lee
- Patrick Gallagher
- Takashi Taniguchi
- Vladimir I. Fal’ko
Organizations
- Air Force Office of Scientific Research
- Gordon and Betty Moore Foundation
- Lloyd's Register Foundation
- National Institute for Materials Science
- Stanford University
- University of Manchester