title: Two-stage rotational disordering of a molecular crystal surface: C60.
abstract: We propose a two-stage mechanism for the rotational surface disordering phase transition of a molecular crystal, as realized in C60 fullerite. Our study, based on Monte Carlo simulations, uncovers the existence of a new intermediate regime, between a low-temperature ordered (2x2) state, and a high-temperature (1x1) disordered phase. In the intermediate regime there is partial disorder, strongest for a subset of particularly frustrated surface molecules. These concepts and calculations provide a coherent understanding of experimental observations, with possible extension to other molecular crystal surfaces.
authors.affiliation: Facultés Universitaires Notre-Dame de la Paix, Rue de Bruxelles 61, B-5000 Namur, Belgium.
authors.forename: C
authors.initials: C
authors.lastname: Laforge
authors.forename: D
authors.initials: D
authors.lastname: Passerone
authors.forename: A B
authors.initials: AB
authors.lastname: Harris
authors.forename: P
authors.initials: P
authors.lastname: Lambin
authors.forename: E
authors.initials: E
authors.lastname: Tosatti