Abstract
Electronic and structural properties of , , and reconstructed surfaces have been studied by synchrotron-radiation photoelectron spectroscopy and scanning tunneling microscopy (STM). Based on the difference spectrum of As core-level spectra of , measured in different surface-sensitivity conditions, as well as the line shape of the As emission from the Sb-induced surface, we give evidence that the As spectra of and consist of two surface-core-level-shifted components. One of them is shifted about to the lower kinetic energy from the bulk component. On the basis of the relative component intensities, this surface-shifted As component is assigned to the emission from the first-layer As dimers in the established model of the surface. The other component, shifted about to the higher kinetic energy, is connected to the third-layer As-dimer site. The comparison of the core-level results between and suggests that the phase, which has one As dimer in both the first and third atomic layers per unit cell, exists on , similarly to the case of , as predicted in theory but not observed to date. Furthermore, the STM observation of the phase is reported.
- Received 1 February 2005
DOI:https://doi.org/10.1103/PhysRevB.72.045321
©2005 American Physical Society