Observing the Quantization of Zero Mass Carriers in Graphene

Published

May 15, 2009

Author(s)

Joseph A. Stroscio, Gregory M. Rutter, D. L. Miller, K. Kubista, W. A. de Heer, Phillip N. First

Abstract

Application of a magnetic field to conductors causes the charge carriers to circulate in cyclotron orbits with quantized energies called Landau levels (LLs). These are equally spaced in normal metals and two-dimensional electron gases. In graphene, however, the charge carrier velocity is independent of their energy (like massless photons). Consequently, the LL energies are not equally spaced and include a characteristic zero-energy state (the n = 0 LL). With the use of scanning tunneling spectroscopy of graphene grown on silicon carbide, we directly observed the discrete, non-equally spaced energy-level spectrum of LLs, including the hallmark zero-energy state of graphene. We also detected characteristic magneto-oscillations in the tunneling conductance and mapped the electrostatic potential of graphene by measuring spatial variations in the energy of the n = 0 LL.

Citation

Science

Volume

324

Pub Type

Journals

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Keywords

graphene, SiC, scanning tunneling microscopy, Landau quantization

Citation

Stroscio, J. , Rutter, G. , Miller, D. , Kubista, K. , de, W. and First, P. (2009), Observing the Quantization of Zero Mass Carriers in Graphene, Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=901095 (Accessed December 30, 2024)