It was recalled that GaSb(001) apparently violates the electron counting rule in forming a reconstruction featuring long Sb-dimer chains, rather than the c(4 x 4) reconstruction found in all other arsenide and antimonide III–V compounds in the V-rich regime. It was found that an alternative strategy, that in fact satisfies the ECR, was followed by the Sb-rich GaSb(001) surface, whereby long Sb-dimer chains were stabilized by randomly distributed subsurface Ga antisite defects. The excess of surface Sb drives the defect formation that in turn stabilizes the surface in a metastable phase. The transition to the c(4 x 4) reconstruction, where the electron counting rule was instead satisfied through missing dimers, was therefore inhibited. The conclusions were supported by ab initio simulations of experimental reflectance anisotropy spectra.

Spontaneous Formation of Surface Antisite Defects in the Stabilization of the Sb-Rich GaSb(001) Surface. C.Hogan, R.Magri, R.Del Sole: Physical Review Letters, 2010, 104[15], 157402