Physical review. B, Condensed matter
Kosterlitz-Thouless transition in multipolar systems
Mai Suan Li, Marek Cieplak
Abstract
Using analytical and discretized Migdal-Kadanoff renormalization-group methods it is shown that similar to the standard XY model the two-component uniform multipolar systems undergo a Kosterlitz-Thouless transition in two dimensions. The critical behavior of the multipole-multipole correlation function is governed by a set of critical exponents that depend on the rank t of multipole moments. At the Kosterlitz-Thouless transition they become universal for all systems. An exactly renormalizable multipolar model is introduced. The behavior of this model on fractal and hierarchical lattices is studied. The T=0 scaling exponent of the two-component multipolar systems on a Sierpinski carpet is shown to be negative, so no Kosterlitz-Thouless transition can be expected to take place in this case.