Low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), and photoelectron spectroscopy have been used to study an ordered structure formed by Ge atoms deposited onto the Au(111) surface. Based on a careful analysis of STM images and LEED patterns, we propose a ((5)(8) (0)(-14)) unit cell for the atomic structure of the Ge layer. Core-level data indicate that some Ge atoms diffuse into the Au(111) crystal during annealing after deposition at room temperature. This is further corroborated by angle-resolved photoelectron spectroscopy (ARPES) measured for different amounts of Ge remaining after sputtering and annealing. The results of the ARPES study clearly disprove an earlier assignment of a parabolic band, centered at normal emission, as a part of a Dirac cone of germanene.
Funding Agencies|Swedish Research Council [621-2014-4764, 2008-6582]