Density functional theory calculations were performed in order to study the geometric structure of the P vacancy on the InP(110) surface. The stable structure of the P vacancy depended critically on its charge state. For a (+1) charged P vacancy, the non-symmetrical configuration with one re-bonded dimer was favored, while the symmetric configuration exhibited a saddle point behavior. For a (–1) charged P vacancy, both the symmetric and nonsymmetrical configurations were local minima, where the symmetric configuration has the lowest energy. Using the nudged elastic band method, the reaction path and energy barrier between 2 configurations for both (+1) and (–1) charged vacancies were determined. The simulated scanning tunneling microscopy images of the P vacancy on p-type and n-type InP(110) surfaces were calculated and compared with the available experimental results. It was supposed that the observed scanning tunnelling microscopic image of the P vacancy was an average resulting from thermal flipping between 2 possible configurations.

Structure of the P Vacancy on the InP(110) Surface from First Principles. M.C.Qian, M.Göthelid, B.Johansson, S.Mirbt: Physical Review B, 2003, 67[3], 035308 (5pp)