Modified Migdal-Kadanoff renormalization for the spin-(1/2 anisotropic Heisenberg model
Felix Lee, H. H. Chen, H. C. Tseng
The spin-(1/2 anisotropic Heisenberg model is studied by a modified Migdal-Kadanoff method, called the cluster-decimation approximation. The free energy for a small cluster of spins with an appropriate boundary condition is assumed to be preserved in the bond-moving step and the approximate decimation of Suzuki and Takano is adopted in the site-decimation step. Critical temperatures obtained by the present method are in general much better than those determined by preserving the high-temperature series expansion of the free energy. In particular the XY fixed point and the isotropic Heisenberg fixed point for the square lattice are not found in the present calculation.
Physical review. B, Condensed matter•Jul 1, 1988•7 citations