自旋派尔斯链热力学性质研究  

Thermodynamic properties in spin-Peierls chain

作　　者：江学范[1] 

机构地区：[1]常熟理工学院物理与电子科学系,江苏常熟215500

出　　处：《常熟理工学院学报》2005年第2期28-32,共5页Journal of Changshu Institute of Technology

基　　金：supported by the National Science Foundation of Jiangsu Educational Department

摘　　要：结合热相干态近似和玻色化技术,扩展应用量子自洽理论讨论了低温下自旋派尔斯链的磁性激发和热力学性质。研究发现自旋激发能隙随温度升高而单调下降,于派尔斯相变点(TP)消失,在TP附近,比热随温度升高而迅速增强。TP的标度关系符合TP∝δ(0)0.66。Combining the thermal coherent states with the bosonization technique,we develop a self_consistent quantum approach to investigate the dimerized antiferromagnetic Heisenberg chain at finite temperature.In the case of weak dimerization,temperature dependences of the magnetic excited energy gap and the specific heat are calculated analytically.The energy gap monotonically decreases with increasing temperature until it vanishes at the Peierls transition temperature T_P.The specific heat is strongly enhanced near T_P.It is also found that there is a scaling behavior of T_P as a function of the zero_temperature dimerization δ_0 as T_P ∝δ~v_0 with v=(0.66) for small δ_0.Our results are qualitatively consistent with experimental data observed in CuGeO_3.

关 键 词：性质研究 自旋 链 温度升高 热力学性质 自洽理论 扩展应用 单调下降 标度关系 玻色化 相干态 相变点 TP 激发 近似 磁性 低温 量子 能隙 比热 

分 类 号：O413.1[理学—理论物理] TS202.3[理学—物理]