Melting behavior of the beta-Pb/Ge(111) structure
Reedijk MF, Arsic J, Kaminski D, Poodt P, Knops H, Serrano P, Castro GR, Vlieg E
PHYSICAL REVIEW B  67 (16): art. no. 165423 APR 15 2003

Abstract:
The two-dimensional phase transition of the (root3xroot3) R30degrees-Pb/Ge(111) surface is analyzed using surface x-ray diffraction. The critical exponents beta, nu, and gamma have been determined. These exponents exhibit mean-field behavior indicating a long-range interaction potential for the Pb atoms. Deviations from the mean-field behavior, due to finite-size effects, occur at temperatures close to T-c.