Dynamics of Two-Dimensional Melting on a Periodic Substrate

Quasielastic and inelastic neutron scattering has been used to study the diffusion and the layer shear elastic constant across the melting transition of incommensurate K and Rb layers intercalated in graphite. The melting of the quasi two-dimensional layers on a periodic graphite substrate is characterized by a smooth transition from a solidlike to a liquidlike dynamical behavior via unpinning of discommensuration domain walls.