GAAS(110) SURFACE ELECTRONIC-STRUCTURE BY METASTABLE DEEXCITATION SPECTROSCOPY

Metastable deexcitation spectroscopy was applied to study the surface valence electronic structure of clean cleaved GaAs(110). Metastable de excitation spectroscopy was flanked by angle-resolved photoemission. A n effective surface density of states was derived from the experimenta l spectrum through deconvolution. Two groups of states were observed i n the 0-4 and 5-8 eV range of binding energy, respectively. These feat ures were ascribed to emission from surface states. A plane-by-plane t ight-binding density-of-states calculation was performed. More quantit ative insights were obtained by comparing experimental and theoretical results. The most prominent feature of the first group of states of d econvolution was assigned to surface state A(5). Contributions from st ates A(4), A(3), A(1)', and A(2)' were also observed. The doublet of t he second group of features was identified with C-2 and C-1. Relative amplitudes of effective surface density of states were related to surf ace charge density.