A GRAND ISOSTRESS ENSEMBLE MONTE-CARLO STUDY OF THIN-FILMS UNDER SHEAR

Thin films of monatomic fluid constrained between two plane-parallel s tructured solid walls have been simulated by Monte Carlo under conditi ons (fixed temperature, chemical potential and normal stress or load) prevailing in high-precision measurements of surface forces. Several p hases of the film (corresponding to different numbers of layers of flu id parallel with the walls) are generally consistent with these condit ions, but only one is thermodynamically stable; the others are metasta ble. When the walls are properly aligned, epitaxial solidlike phases a re stable. These melt under shear, eventually becoming metastable, whe reupon a drainage (or imbibition) transition occurs, leading to a stab le phase with fewer (or more) layers.