Two-dimensional electron gas at InAs(100)1x2/1x4Pb

Upon deposition of one lead monolayer on the clean, In-terminated InAs(100)4 x 2/c(8 x 2) surface, we have obtained a new 1 x 2/1 x 4 superstructure and have studied its electronic properties by synchrotron radiation photoelectron spectroscopy (valence bands and In 4d plus Pb 5d core levels). The markedly increased emission in the vicinity of the Fermi level for this reconstruction, as compared to the bare surface, and its narrow localization in k space are the signature of the formation of a strong two-dimensional electron gas in the sub-surface region. (C) 1998 Elsevier Science B.V. All rights reserved.