Monte Carlo study of linear chain submonolayer structures.Application to Li/W(112)

The lattice gas model for adsorption of alkaline elements on W(112) surface is studied by Monte Carlo simulations. The model includes dipole--dipole interaction as well as long-range indirect interaction. The numerical results show that truncation of the indirect interaction even at 200$\AA$ may change a phase diagram, i.e., new phases containing domain walls might occur. It is demonstrated that a defected phase can exist at high temperatures even if it is not stable at T=0. The phase diagram for Li/W(112) is constructed and long periodic chain structures (9*1), (6*1), (4*1), (3*1), and (2*1) are found to be stable at low temperatures. Role of thermal fluctuation is discussed by comparison of Monte Carlo results with mean field approximation results.Comment: 7 pages, 7 figures, REVTe

SOS model of overlayer induced faceting

A solid-on-solid model is proposed to describe faceting of bcc(111) metal surface induced by a metal overlayer. It is shown that the first order phase transition occurs between faceted {211} or {110} and disordered phases. The ordered phases consist of large 3-sided pyramids with {211} facets or {110} facets. It is shown that the high-temperature disordered phase has not planar bcc(111) structure but faceted disordered structure. Hysteresis effects were observed when the system was warmed above the transition temperature and then cooled down. Temperature dependence of LEED patterns for faceted and disordered phase are calculated in kinematic approximation.Comment: 8 pages, 10 figures, REVTe