ROUGHENING OF THE PB(110) SURFACE - COMBINED MONTE-CARLO AND MOLECULAR-DYNAMICS STUDY

The roughening transition on the Pb (110) surface has been studied usi ng a combination of lattice-gas Monte Carlo and molecular-dynamics met hods in conjunction with a many-body glue potential. Lattice-gas Monte Carlo simulations yield a roughening transition temperature of approx imately T-R(LGMC) approximate to 1100 K. Molecular-dynamics simulation s, which account for surface relaxation and lattice vibrations, detect the roughening transition at T-R(MD) approximate to 545 K, above the high-resolution low-energy diffraction measurements of T-R(EXP) approx imate to 415 K. The anisotropic body-centered solid-on-solid model is used in the interpretation of these results. The time scale of local r oughening at 545 K is about 0.6 ns. The time evolution of the Pb (110) surface from an initially smooth to a rough configuration is illustra ted by the use of modem visualization techniques. Means for improving the theoretical results are discussed.