高Tc超导体的反铁磁理论计算

考虑到高T_c超导材料层状桔构特点,从三维各向异性Hubbard模型出发,在大U时导出了自旋波线性近似下的有效哈密顿量。利用格林函数运动方程技术,计算了系统的子晶格磁化强度、内能、比热、平行磁化率和垂直磁化率等物理量。结果表明,层间和层内反铁磁耦合强度之比δ=J_⊥/J对这些物理量有重要影响。在低温T?2J(2+δ)/k_B下,确定了特征温度T₀=2J(2δ(2+δ))^1/2/k_B,分别给出了T?T₀和T?T₀时,这些物理量的渐近表达式。关键词：

ANTIFERROMAGNETIC THEORETICAL CALCULATION FOR HlGH-Tc SUPERCONDUCTORS

Considering layer-structural characteristico of high-T_c superconductors, the effective Hamiltonian is derived within linear spin wave approximation for aniso-tropic three-dimensional Hubbard model in the large U limit. The Sublattice magnetization, internal energy, Specific heat, parallel and perpindicular susceptibilies of the system are Calculated by using the equation of motion for matrix Green's function. It is shown that the ratio (δ=J_⊥/J) of antiferromagnetic interplanar Coupling to planar coupling has an important effect upon these quantities. In the Low temperature regime T?2J(2+δ)/k_B, a characteristic temperature T₀=2J(2δ(2+δ))^1/2/k_B is given, the asympototic expressions of these quantities are respectively obtained for T?T₀ and T?T₀.
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