Surface structure of GaAs(0 0 1)-c(4 × 4) studied by LEED intensity analysis

From the results of scanning tunneling microscopy and intensity analysis of low-energy electron diffraction, it was confirmed that under the conditions of molecular beam epitaxy using As4, the c(4 × 4) reconstruction on GaAs(0 0 1) has two phases with different surface compositions. While the lesser As coverage phase has a structure that contains three As–Ga dimers per unit cell, the higher As coverage phase has a structure containing three As–As dimers with 2 mm symmetry. Detailed atomic geometries for the two phases were presented.