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 C${}_{60}$ fullerite. Our study, based on Monte Carlo simulations, uncovers the existence of a new intermediate regime, between a low temperature ordered $(2\times 2)$ state, and a high temperature $(1\times 1)$ 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.

4 pages, 2 figures

Cited by in corpus (4)

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