二维反铁磁海森堡模型的量子蒙特卡洛模拟  

Quantum Monte Carlo simulation of tow-dimensional antiferromagnetic Heisenberg model

作　　者：周琼[1] 李晋斌[1] 

机构地区：[1]南京航空航天大学理学院,江苏南京200016

出　　处：《广西大学学报（自然科学版）》2011年第2期334-338,共5页Journal of Guangxi University（Natural Science Edition）

基　　金：教育部博士点基金资助项目(20070287062);南京航空航天大学青年科技创新基金项目(Y1093-081)

摘　　要：采用Stochastic Series Expansion(SSE)量子蒙特卡洛方法对正方晶格中自旋为1/2的反铁磁海森堡模型进行计算机模拟,给出能量、比热及均匀磁化率与温度的变化关系。结果表明:在各向同性情况下,温度约在kT/J=0.6处,比热有峰值,温度约在kT/J=1处,均匀磁化率达到饱和,且晶格大小的有限性对热力学量与温度的变化行为有一定的影响;在各向异性情况下,能量随着各向异性参数g的增加而减小,且在低温区,当g<1时,均匀磁化率随温度变化比较缓慢,当g>1时,均匀磁化率随温度降低向零指数衰减,在高温区,对不同各向异性参数g,均匀磁化率随温度变化行为趋于一致。The Antiferromagnetic Heisenberg Model with spin 1/2 on a square lattice was simulated by using the Stochastic Series Expansion（SSE） Quantum Monte Carlo Method.The temperature dependence of the internal energy,specific heat and uniform susceptibility was observed.The results showed that specific heat has a maximum at kT/J=0.6 and uniform susceptibility saturates at kT/J=1 for the isotropy case.And the size of lattice also affects the temperature dependence of these thermodynamic quantities.For the anisotropy case,energy decreases with anisotropic parameter g increasing.Susceptibility changes slowly with temperature for g1 and exponentially decay for g1 in the low temperature region and its behaviors approach consistent for different g in the high temperature region.

关 键 词：反铁磁海森堡模型 量子蒙特卡洛方法 各向异性 热力学性质 温度 

分 类 号：O413.3[理学—理论物理]