Scanning tunneling microscopy images of the equilibrium structure of A- and B-type steps on vicinal GaAs(001) with the (2×4)/c(2×8) reconstruction have been analyzed to determine edge and kink energies. The values of the edge energies are low (implying that the equilibrium steps will be quite rough at room temperature), and anisotropic by a ratio of ∼6:1. The data provide evidence for a kink-kink interaction, found only in the A steps, which is short range and repulsive.

• Received 23 March 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.743