Green's function theory of quasi-two-dimensional spin-half Heisenberg ferromagnets: Stacked square versus stacked kagome lattices

[摘要] We consider the thermodynamic properties of the quasi-two-dimensional spin-half Heisenberg ferromagnet on stacked square and stacked kagome lattices by using the spin-rotation-invariant Green's function method. We calculate the critical temperature T-C, the uniform static susceptibility chi, the correlation lengths xi(nu), and the magnetization M and investigate the short-range order above T-C. We find that T-C and M at T > 0 are smaller for the stacked kagome lattice, which we attribute to frustration effects becoming relevant at finite temperatures.

[发布日期] 2005-12-01

[关键词] SHORT-RANGE ORDER;NEEL TEMPERATURE;WAVE THEORY;ANTIFERROMAGNET