Voltage-dependent scanning-tunneling microscopy of a crystal surface: Graphite

We discuss the possible application of the scanning tunneling microscope (STM) to surface electronic spectroscopy, with an explicit calculation of the voltage-dependent tunneling current for an ideal STM experiment performed on graphite. We study how surface and bulk electronic states are reflected in the tunneling J-V spectra, and show that empty surface states of graphite may be well discriminated against bulklike structures by considering STM spectra at different tip-surface separations.