An on/off Berry phase switch in circular graphene resonators

@article{Ghahari2017AnOB,
  title={An on/off Berry phase switch in circular graphene resonators},
  author={Fereshte Ghahari and Daniel Walkup and Christopher Guti{\'e}rrez and Joaquin F. Rodriguez-Nieva and Yue Zhao and Jonathan Wyrick and Fabian D Natterer and William G. Cullen and Kenji Watanabe and Takashi Taniguchi and Leonid S. Levitov and Nikolai B. Zhitenev and Joseph A. Stroscio},
  journal={Science},
  year={2017},
  volume={356},
  pages={845 - 849}
}
Flicking the Berry phase switch 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… 

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