Staircase model of GaSb(001)(1×3)andc(2×6)phases

Abstract

We show that the $(1\ifmmode\times\else\texttimes\fi{}3)$ and $c(2\ifmmode\times\else\texttimes\fi{}6)$ diffraction patterns of the reconstructed GaSb(001) surface are the result of characteristic disorder in the positions of the $(4\ifmmode\times\else\texttimes\fi{}3)$ reconstructed surface unit cells. The reconstructed cells form uniform rows in the $4\ifmmode\times\else\texttimes\fi{}$ direction with the rows shifted with respect to each other. Random shifts of the rows result in the $(1\ifmmode\times\else\texttimes\fi{}3)$ diffraction pattern. If only shifts by $\ifmmode\pm\else\textpm\fi{}1/4$ between the unit-cell rows are allowed, we obtain the $c(2\ifmmode\times\else\texttimes\fi{}6)$ pattern. Our results agree with the electron counting rule, previous scanning tunneling microscopy studies, and our own reflection high-energy electron-diffraction observations.