Elastic Metastability: Thermally Activated Snap-through Transitions in Nanostructures

Abstract: The morphological snap-through transition of a bistable elastic structure typically requires external loading, unless it is miniaturized to the nanoscale, where thermal fluctuations play a significant role. We propose that metastability can emerge in microscopic elastic systems when coupled to a thermal environment, giving rise to thermally activated transitions between metastable configurations. Using atomistic simulations combined with rare event methods, we demonstrate that snap-through events can occur as well-defined thermally activated transitions in a geometrically constrained graphene nanoribbon. Well-tempered metadynamics is employed to determine the transition energetics and pathways. Notably, the temperature dependence of the transition rate constant is accurately described by generalized transition state theory in terms of the Landau free energy. This study introduces a theoretical framework for understanding elastic metastability, extends reaction rate theory to nanomechanical systems, and suggests strategies for designing temperature-responsive nanodevices.