Microscopic mechanisms of surface phase transitions on InAs(001)

Microscopic mechanisms of the (2x4) to (4x2) 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 As-2 desorption. The unusually high prefactors observed experimentally are traced back to the microscopic As-2 desorption processes. Calculated interactions between As dimers explain the observed disorder of the mixed alpha2(2x4) and beta2(2x4) reconstructions and are not responsible for observed first order behavior of the transition.