Order-disorder phase transition of vacancies in surfaces: The case of Sn/Cu(001)-0.5 ML

J. E. Gayone,1 A. Carrera,1 O. Grizzi,1 S. Bengio,1 E. A. Sanchez,1 J. Martinez-Blanco,2 E. G. Michel,2 J. D. Fuhr,1 and H. Ascolani1 1Centro Atomico Bariloche, CNEA, and CONICET, Av. E. Bustillo 9500, R8402AGP Bariloche, Argentina 2Departamento de Fisica de la Materia Condensada and Instituto Universitario de Ciencia de Materiales “Nicolas Cabrera,” Universidad Autonoma de Madrid, 28049 Madrid, Spain Received 31 May 2010; published 15 July 2010