Surface Incommensurate Structure in an Anisotropic Model with competing interactions on Semiinfinite Triangular Lattice
arXiv:cond-mat/9611193 · doi:10.1088/0305-4470/30/12/010
Abstract
An anisotropic spin model on a triangular semiinfinite lattice with ferromagnetic nearest-neighbour interactions and one antiferromagnetic next-nearest-neighbour interaction is investigated by the cluster transfer-matrix method. A phase diagram with <2> antiphase, ferromagnetic, incommensurate, and disordered phase is obtained. The bulk uniaxial incommensurate structure modulated in the direction of the competing interactions is found between the <2> antiphase and the disordered phase. The incommensurate structure near the surface with free and <2> boundary condition is studied at different temperatures. Paramagnetic damping at the surface and enhancement of the incommensurate structure in the subsurface region at high temperatures and a new subsurface incommensurate structure modulated in two directions at low temperatures are found.
13 pages, plainTex, 11 figures, paper submitted to J. Phys. A