Step stiffness and equilibrium island shape of Si(100) surface: Statistical-mechanical calculation by the imaginary path weight random-walk method

A step on a surface is well-modeled by an interface in the Ising model. We calculate anisotropic interface tension and interface stiffness for the square-lattice Ising model with both nearest-neighbor and next-nearest-neighbor interactions by an extended Feynman-Vdovichenko's random-walk method. The result gives a satisfactory explanation for experimentally measured step tension, step stiffness and island shape on the Si(100) surface. (C) 1997 Elsevier Science B.V.