The dependence of the structural relaxation around phosphorous vacancies in InP(110) and GaP(110) surfaces on their charge state was investigated by scanning tunneling microscopy. Two charge transition levels were localized within the band gap. The symmetry of the vacancies is lowered with an increasing number of electrons bonded in the electronic defect states. The vacancies on InP(110) and GaP(110) surfaces have essentially the same structure.

• Received 26 July 1993

DOI:https://doi.org/10.1103/PhysRevLett.72.840