Melting and crystallisation on a corrugated surface

Melting and crystallisation of a triangular electron solid on a commensurate, sinusoidally corrugated surface (of wavelength lambda = square root 3a/2, a=lattice spacing) are studied by the molecular dynamics method. If the height of the corrugation U0is less than a certain critical value Uc, melting is found to be a grain-boundary-mediated first-order transition. However, for U0>Uc the transition is continuous and induced by a small density of defects.