Constrained deformation of a confined solid: a strain induced crystal-smectic transition

We report results of computer simulations of two-dimensional hard disks confined within a quasi one-dimensional ``hard-wall'' channel, a few atomic radii wide. Starting from a commensurate triangular solid a rescaling of the system size parallel to the channel length introduces a rectangular distortion of the solid which, beyond a critical limit, phase separates into alternating bands of solid and smectic phases. The resulting solid- smectic interfaces are broad and incorporate misfit dislocations. The stress-strain curve shows large plastic deformation accompanying the crystal-smectic transition which is reversible. The smectic phase eventually melts into a modulated liquid with a divergent Lindemann parameter.