Reversible superstructural transitions on the GaAs(001) surface under the selective effect of iodine and cesium

The selective interaction of the iodine and cesium atoms with the GaAs(001) surface, which leads to a decrease in the bond energy of the Ga and As surface atoms, respectively, owing to the redistribution of the electron density in the near-surface region under the effect of electronegative and electropositive adsorbates, has been experimentally investigated. This selective interaction makes it possible to remove alternately the Ga and As monolayers in the iodine and cesium adsorption followed by heating at $T\le450^\circ$C and, thus, to implement reversible low-temperature transitions between the Ga-and As-stabilized superstructures, as well as the atomic layer etching of the semiconductor with the physically ultimate monolayer accuracy.