Abstract
One of the enduring challenges in graphene research and applications is the extreme sensitivity of its charge carriers to external perturbations, especially those introduced by the substrate. The best available substrates to date, graphite and hexagonal boron nitride (), still pose limitations: graphite being metallic does not allow gating, while both and graphite, having lattice structures closely matched to that of graphene, may cause significant band structure reconstruction. Here we show that the atomically smooth surface of exfoliated provides access to the intrinsic electronic structure of graphene without these drawbacks. Using scanning tunneling microscopy and Landau-level (LL) spectroscopy in a device configuration that allows tuning of the carrier concentration, we find that graphene on is ultraflat, producing long mean free paths, while avoiding band structure reconstruction. Importantly, the screening of the substrate can be tuned by changing the position of the Fermi energy with relatively low gate voltages. We show that shifting the Fermi energy from the gap to the edge of the conduction band gives rise to enhanced screening and to a substantial increase in the mean free path and quasiparticle lifetime. substrates thus provide unique opportunities to access the intrinsic electronic properties of graphene and to study in situ the effects of screening on electron-electron interactions and transport.
- Received 25 July 2014
- Corrected 13 November 2014
DOI:https://doi.org/10.1103/PhysRevLett.113.156804
© 2014 American Physical Society
Corrections
13 November 2014
Erratum
Publisher’s Note: : Choice Substrate for Accessing and Tuning the Electronic Properties of Graphene [Phys. Rev. Lett. 113, 156804 (2014)]
Chih-Pin Lu, Guohong Li, K. Watanabe, T. Taniguchi, and Eva Y. Andrei
Phys. Rev. Lett. 113, 249901 (2014)
Synopsis
Giving Graphene a Rest
Published 9 October 2014
Molybdenum disulfide may provide an ideal substrate for supporting graphene.
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