Electronic structure and UPS of the misfit chalcogenide (SnS)NbS2 and related compounds

Based on the self-consistent band structure we present density-of-states (D OS) functions for a supercell structure (SnS)(1.2)NbS2 and discuss the inte rcalation effects. An ab initio UPS spectrum of (SnS)NbS2 is compared to th e experiment. The prototypes of the layer constituents of the misfit, PbS ( NaCl) and 2H-NbS2 and NbSe2, are studied; theoretical results are compared with available XPS and optical measurements. For PbS both relativistic effe cts and local field effects are found important. Experimental angle resolve d UPS for NbSe2 are compared to k(parallel to)-projected DOS functions. (C) 2001 Elsevier Science B.V. All rights reserved.