CALCULATION OF THE ANISOTROPIC DOMAIN-WALL ENERGY SIGMA(NU, PHI T) AND OF DOMAIN SHAPES - MC SIMULATIONS FOR THE 3D ISING-MODEL

In a 3d s.c. Ising system a domain wall with a given arbitrary orienta tion is produced by applying suitable boundary conditions. For various temperatures the domain wall energy sigma(v, phi) is determined by me ans of a modified Metropolis procedure. Series expansions are given in terms of polynomials of the cartesian components /n(i)/ I Of the wall normal exhibiting the proper cubic symmetry and in terms of surface s pherical harmonics Y-l(m)(v, phi). In addition, the temperature depend ence of the free energy sigma(s) of surface steps on lowest energy (10 0)-walls was calculated. Furthermore the shape of the domains was dete rmined as a function of temperature both by the Wulff construction mak ing use of the function sigma(v, phi) and directly by MC simulations.