A Self-Consistent Gaussian Study On Phase Transition and Critical Exponents of Kagome Lattice

The low temperature dynamics of the classical Heisenberg antiferromagnet with nearest neighbor interaction on the frustrated kagome lattice is studied by using a self-consistent Gaussian method (SCGA). The structure factor of this lattice for different temperatures has been calculated and plotted. It has been seen that by decreasing the temperature, several maxima with same height has been appeared which reveals that the system doesn’t have a certain ground state. By projecting the structure factor on the plane, pinch point behavior is also considered, and it has been shown that by decreasing the temperature, pinch points are becoming sharper, which suggests a highly frustrated lattice. Then the single-ion anisotropy term is added to Hamiltonian and phase transition temperature and critical exponents of kagome lattice has been calculated by using the SCGA method. It has been seen that by decreasing the single ion anisotropy coefficient from D=1 to D=0.2, phase transition temperature decreases from Tc=0.4 to 0.15K which are well consistent with Monte Carlo simulation results.