Real-Space Imaging of Alternate Localization and Extension of Quasi Two-Dimensional Electronic States at Graphite Surfaces in Magnetic Fields

2005/11/30 by Y. Niimi, H. Kambara, T. Matsui +2 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.dis-nn

paper · pdf · doi:10.1103/physrevlett.97.236804

published as Phys. Rev. Lett. 97, 236804 (2006) · 4 pages, 4 figures

arxiv created 2006/12/22 · arxiv updated 2009/12/01

Abstract

We measured the local density of states (LDOS) of a quasi two-dimensional (2D) electron system near point defects on a surface of highly oriented pyrolytic graphite (HOPG) with scanning tunneling microscopy and spectroscopy. Differential tunnel conductance images taken at very low temperatures and in high magnetic fields show a clear contrast between localized and extended spatial distributions of the LDOS at the valley and peak energies of the Landau level spectrum, respectively. The localized electronic state has a single circular distribution around the defects with a radius comparable to the magnetic length. The localized LDOS is in good agreement with a spatial distribution of a calculated wave function for a single electron in 2D in a Coulomb potential in magnetic fields.

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