A Reconfigurable Shape-memory Surface

The mechanical response of a graphene monolayer with equal numbers of pentagon and heptagon disclinations arranged in a kagome-like superlattice is modeled with semiclassical molecular dynamics. The pentagon disclinations form cones with an Ising degree of freedom in their up/down orientation, yielding a reconfigurable surface with a large number of distinct metastable shapes, unlike traditional membranes which typically have a single metastable shape. A complete 'zoo' of such shapes for a small patch of this material is enumerated and analyzed to uncover the “density of shapes” and the effective interactions between these Ising degrees of mechanical freedom.