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从双子晶格Hubbard模型出发,应用变分泛函积分方法,研究了巡游电子反铁磁性.该方法的关键在于:对Hubbard哈密顿量的相互作用部分作Stratonovich-Hubbard变换时,采用连续分解方案,导致自旋涨落与电荷涨落的分离,从而能更好地描述两类涨落所具有的相反倾向的性质.在连续分解中所引入的参数由变分原理确定,从而消除了泛函积分理论中的“不确定性”困难.本文还对半满带情形作了数值研究,计算了基态性质,奈耳温度,磁化强变以及顺磁磁化率等.与Hasegawa理论比较,在磁化率的温度依赖行为方面有一定改进.
Based on the Gemini Hubbard model, the variational functional integral method is applied to study the antiferromagnetic properties of cruise electron. The key point of this method is that when the Stratonovich-Hubbard transform of the interacting part of the Hubbard Hamiltonian is used, , Resulting in the separation of spin fluctuations and charge fluctuations, which can better describe the nature of the opposite tendency of the two types of fluctuations.The parameters introduced in the continuous decomposition are determined by the variational principle, thus eliminating the functional Integral theory of the “uncertainty” of the difficulty.In this paper, we also make a numerical study of the half-filled with the situation, calculated the ground state properties, Naai temperature, magnetization change and paramagnetic susceptibility, etc. Compared with the Hasegawa theory, the magnetic susceptibility There is a certain improvement in temperature-dependent behavior.