Lifetime of undercooled wetting layers

Abstract

The recently observed large hysteresis effects in undercooling or overheating of wetting layers in systems with a prewetting transition are shown to be a simple consequence of the geometry of the phase diagram. In order to estimate quantitatively the lifetime of such metastable layers, one has to calculate the excess free energy ${\mathit{E}}_{\mathit{c}}$ of the corresponding critical nuclei. For the case of undercooling we determine ${\mathit{E}}_{\mathit{c}}$ as a function of chemical potential μ for a fixed temperature T well below the wetting transition point ${\mathit{T}}_{\mathit{w}}$. For overheating ${\mathit{E}}_{\mathit{c}}$ is known from previous calculations as a function of T at bulk coexistence μ=${\mathrm{\mu }}_{\mathit{c}}$.