Scanning Tunneling Spectroscopy of Graphene on Graphite

TL;DR

This study uses high magnetic field scanning tunneling spectroscopy to analyze graphene on graphite, revealing Landau levels and electronic interactions, and providing insights into substrate coupling and quasiparticle properties.

Contribution

It demonstrates a method to identify graphene and assess substrate coupling through Landau level spectroscopy at low temperatures and high magnetic fields.

Findings

Observation of Landau levels in graphene on graphite.

Determination of Fermi velocity and quasiparticle lifetime.

Insights into electron-phonon and electron-electron interactions.

Abstract

We report low temperature high magnetic field scanning tunneling microscopy and spectroscopy of graphene flakes on graphite that exhibit the structural and electronic properties of graphene decoupled from the substrate. Pronounced peaks in the tunneling spectra develop with field revealing a Landau level sequence that provides a direct way to identify graphene and to determine the degree of its coupling to the substrate. The Fermi velocity and quasiparticle lifetime, obtained from the positions and width of the peaks, provide access to the electron-phonon and electron-electron interactions.