The interaction potential between charged P vacancies on (110) surfaces was deduced from scanning tunnelling microscopic measurements of their correlation. It was found to have the functional form of a screened Coulomb potential, except at very short distances. A vacancy charge of +1 was derived from the measurements. The maximum repulsion was 0.065eV, and the range was 3nm.

P.Ebert, X.Chen, M.Heinrich, M.Simon, K.Urban, M.G.Lagally: Physical Review Letters, 1996, 76[12], 2089-92