GaAs(110) surface electronic structure by metastable deexcitation spectroscopy.

Abstract

Metastable deexcitation spectroscopy was applied to study the surface valence electronic structure of clean cleaved GaAs(110). Metastable deexcitation spectroscopy was flanked by angle-resolved photoemission. An effective surface density of states was derived from the experimental spectrum through deconvolution. Two groups of states were observed in the 0--4 and 5--8 eV range of binding energy, respectively. These features were ascribed to emission from surface states. A plane-by-plane tight-binding density-of-states calculation was performed. More quantitative insights were obtained by comparing experimental and theoretical results. The most prominent feature of the first group of states of deconvolution was assigned to surface state ${\mathit{A}}_{5}$. Contributions from states ${\mathit{A}}_{4}$, ${\mathit{A}}_{3}$, ${\mathit{A}}_{1}^{\ensuremath{'}}$, and ${\mathit{A}}_{2}^{\ensuremath{'}}$ were also observed. The doublet of the second group of features was identified with ${\mathit{C}}_{2}$ and ${\mathit{C}}_{1}$. Relative amplitudes of effective surface density of states were related to surface charge density.