海森堡亚铁磁自旋链的基态性质——自洽自旋波分析

The Ground State Properties of Heisenberg Ferrimagnetic Spin Chains ——The Self-consistent Spin-Wave Analysis

利用自洽的自旋波方法解析地研究了由两种不同的自旋所构成的海森堡亚铁磁 (ferri magnetic)自旋链的基态性质 ,并得到了该系统的两支激发谱 .在平均场近似下 ,给出了两种自旋z轴分量基态的平均值 .在低温时 ,系统的比热随温度的变化规律为T12 .这些结果同量子蒙特卡罗(QMC)和Schwinger玻色子平均场理论所得结果相一致 .

The ground state properties of Heisenberg frimagnetic spin chains ,which consist of two kinds of spin , by employing a self-consistent spin-wave method,were analytically investigated.Precise mean estimates of z -axis component of two kinds of spin by using mean field approximation are given,and two branches of excitation spectrum of the system are obtained. At low temperatures, the specific heat of the system behaves like T 12 . These results are consistent with those orbtained by Quantum Monte Carlo (QMC) technique and Schwinger boson mean field theory.