Affordable Access

Strong Asymmetric Charge Carrier Dependence in Inelastic Electron Tunneling Spectroscopy of Graphene Phonons.

Authors
  • Natterer, Fabian D
  • Zhao, Yue
  • Wyrick, Jonathan
  • Chan, Yang-Hao
  • Ruan, Wen-Ying
  • Chou, Mei-Yin
  • Watanabe, Kenji
  • Taniguchi, Takashi
  • Zhitenev, Nikolai B
  • Stroscio, Joseph A
Type
Published Article
Journal
Physical Review Letters
Publisher
American Physical Society
Publication Date
Jun 19, 2015
Volume
114
Issue
24
Pages
245502–245502
Identifiers
PMID: 26196985
Source
Medline
License
Unknown

Abstract

The observation of phonons in graphene by inelastic electron tunneling spectroscopy has been met with limited success in previous measurements arising from weak signals and other spectral features which inhibit a clear distinction between phonons and miscellaneous excitations. Utilizing a back-gated graphene device that allows adjusting the global charge carrier density, we introduce an averaging method where individual tunneling spectra at varying charge carrier density are combined into one representative spectrum. This method improves the signal for inelastic transitions while it suppresses dispersive spectral features. We thereby map the total graphene phonon density of states, in good agreement with density functional calculations. Unexpectedly, an abrupt change in the phonon intensity is observed when the graphene charge carrier type is switched through a variation of the back-gate electrode potential. This sudden variation in phonon intensity is asymmetric in the carrier type, depending on the sign of the tunneling bias.

Report this publication

Statistics

Seen <100 times