title: Sb/Si(111) adsorption: hidden phase transitions behind Langmuir-like isotherms.
abstract: The experimental study of the thermodynamic and kinetic properties of the Sb/Si(111) interface reveals a surprising behavior: a 2D phase condensates when the Sb coverage increases, indicating strong attractive Sb-Sb interactions, whereas the isotherms present a quasi-Langmuir shape, suggesting that these interactions should be negligible. Ab initio calculations raise this contradiction: while the adsorption site evolves from ternary towards the on-top position with increasing coverage, the character of the Sb-Sb effective interactions changes from repulsive towards attractive, resulting in an almost constant average adsorption energy. A simple (Langmuir) thermodynamic behavior can then be the consequence of a surface phase transition.
authors.affiliation: CRMCN-CNRS, associated to Aix-Marseille Universities (Université de la Mediterranée, Université Paul Cézanne), Campus de Luminy, Case 913, 13288 Marseille Cedex 9, France.
authors.forename: H
authors.initials: H
authors.lastname: Guesmi
authors.forename: L
authors.initials: L
authors.lastname: Lapena
authors.forename: A
authors.initials: A
authors.lastname: Ranguis
authors.forename: P
authors.initials: P
authors.lastname: Müller
authors.forename: G
authors.initials: G
authors.lastname: Tréglia