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Publication Citation: Observing the Quantization of Zero Mass Carriers in Graphene

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Author(s): Joseph A. Stroscio; Gregory M. Rutter; D. L. Miller; K. Kubista; W. A. de Heer; Phillip N. First;
Title: Observing the Quantization of Zero Mass Carriers in Graphene
Published: May 15, 2009
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
Pages: pp. 924 - 927
Keywords: graphene;SiC;scanning tunneling microscopy;Landau quantization
Research Areas: Physics, Condensed Matter Physics, Surface Physics
PDF version: PDF Document Click here to retrieve PDF version of paper (4MB)