Conduction-band structure of graphite single crystals studied by angle-resolved inverse photoemission and target-current spectroscopy.

Abstract

We have measured the conduction-band structure of single-crystalline graphite by angle-resolved inverse photoemission spectroscopy (ARIPES) and target-current spectroscopy (TCS) up to 38.5 eV above the Fermi level. As opposed to azimuthally disordered pyrolytic graphite we find distinct differences in the ARIPES spectra between the \ensuremath{\Gamma}AHK and \ensuremath{\Gamma}ALM planes of the Brillouin zone regarding intensity and energy location of the observed structures. Such differences are much less pronounced in the TCS spectra. The interpretation of a state at the \ensuremath{\Gamma} point near 5 eV above ${E}_{F}$ is discussed in terms of an image-potential state or a bulk-band-derived surface state. The experimental band structure is compared with recent band-structure calculations.