Differential reflectivity and angle-resolved photoemission of PbS(100)

The surface electronic structure of a PbS sample, cleaved in ultra-high-vac uum environment. has been studied with surface differential reflectivity (S DR) and angle-resolved photoelectron spectroscopy (ARUPS). The ARUPS spectr a show the presence of two surface (resonance) states along the two angular directions [0 0 1] and [0 1 1]. SDR shows the existence of a gap of approx imately 2.1 eV and two more optical transitions at energies of 2.7 and 3.1 eV. These transitions have been. tentatively, assigned to different points in the surface Brillouin zone. (C) 2001 Elsevier Science B.V. All rights re served.