An on/off Berry phase switch in circular graphene resonators
Abstract
When an electron completes a cycle around the Dirac point (a particular location in graphene's electronic structure), the phase of its wave function changes by π. This so-called Berry phase is tricky to observe directly in solid-state measurements. Ghahari et al. built a graphene nanostructure consisting of a central region doped with positive carriers surrounded by a negatively doped background. Scanning tunneling spectroscopy revealed sudden jumps in conductivity as the external magnetic field was increased past a threshold value. The jumps occurred when electron orbits started encompassing the Dirac point, reflecting the switch of the Berry phase from zero to π. The tunability of conductivity by such minute changes in magnetic field is promising for future applications.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 26, 2017
- Source ID
- 10.1126/science.aal0212
Entities
People
- Christopher Gutiérrez
- Daniel Walkup
- Fabian D Natterer
- Fereshte Ghahari
- Joaquin F Rodriguez-Nieva
- Jonathan Wyrick
- Joseph A. Stroscio
- Kenji Watanabe
- Leonid Levitov
- Nikolai Zhitenev
- Takashi Taniguchi
- William G Cullen
- Yue Zhao
Organizations
- Harvard University
- Massachusetts Institute of Technology
- National Institute for Materials Science
- National Institute of Standards and Technology
- National Natural Science Foundation of China
- National Science Foundation
- Swiss Federal Institute of Technology in Lausanne
- Swiss National Science Foundation
- United States Army Research Laboratory
- University of Maryland