Microscopic mechanisms of surface phase transitions on InAs(001)

Microscopic mechanisms of the $(2\ifmmode\times\else\texttimes\fi{}4)$ to $(4\ifmmode\times\else\texttimes\fi{}2)$ surface phase transition on InAs(001) are identified using a combination of theoretical and experimental methods. Two distinct transition stages are found, both rate limited by ${\mathrm{As}}_{2}$ desorption. The unusually high prefactors observed experimentally are traced back to the microscopic ${\mathrm{As}}_{2}$ desorption processes. Calculated interactions between As dimers explain the observed disorder of the mixed $\ensuremath{\alpha}2(2\ifmmode\times\else\texttimes\fi{}4)$ and $\ensuremath{\beta}2(2\ifmmode\times\else\texttimes\fi{}4)$ reconstructions and are not responsible for observed first order behavior of the transition.