title: GaAs(001) surface under conditions of low As pressure: evidence for a novel surface geometry
abstract: Using density-functional theory we identify a new low-energy structure for GaAs(001) in an As-poor environment. The discovered geometry is qualitatively different from the usual surface-dimer based reconstructions of III-V semiconductor (001) surfaces. The stability of the new structure, which has a c(8x2) periodicity, is explained in terms of bond saturation and favorable electrostatic interactions between surface atoms. Simulated scanning tunneling microscopy images are in good agreement with experimental data, and a low-energy electron diffraction analysis supports the theoretical prediction.
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors.initials: SH
authors.lastname: Lee
authors.initials: W
authors.lastname: Moritz
authors.initials: M
authors.lastname: Scheffler