MECHANICAL HYSTERESIS ON AN ATOMIC-SCALE

A micromechanical hysteresis associated with intimate atomic force microscopy (AFM) on the Si(100) surface is discovered using ab initio total energy pseudopotential density functional calculations. It is predicted that it is possible to cycle repeatedly between two buckled configurations of a surface dimer along two different paths, one of which involves a discontinuous change of the equilibrium dimer-angle, by varying appropriately the vertical movement of the AFM tip. This microscopic mechanical hysteresis effect should be detectable experimentally in low temperature AFM measurements.