晶格量子涨落对spin-Peierls系统低能量激发态的影响  

Quantum lattice dynamical effects on the low-energy excitations in spin-Peierls systems

作　　者：徐靖[1] 王治国[2] 石云龙[1] 陈宇光[2] 陈鸿[2] 

机构地区：[1]雁北师范学院物理系,大同037000 [2]同济大学物理系,上海200092

出　　处：《物理学报》2004年第11期3882-3887,共6页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :90 3 0 10 2 2和 10 6740 65 );山西省青年科技研究基金 (批准号 :2 0 0 2 10 0 6)资助的课题~~

摘　　要：在非绝热近似下 ,研究了一维spin_Peierls系统中晶格量子涨落对系统性质的影响 ,讨论了系统的二聚化相变、单粒子激发和双粒子束缚态 .结果表明 ,量子晶格涨落会抑制晶格的二聚化 ,破坏系统的spin_Peierls基态稳定性 .在临界点 ,系统发生从二聚化spin_Peierls态向无能隙态的相变 .自旋Using the bosonization technique and Gaussian wave functional method, we investigate the low_energy excitations of a spin_Peierls chain where the spins interact with quantum phonons. The results show that the energy gap of the one_ and two_particle excitation states decrease gradually when spin_phonon coupling constant decreases or the phonon frequency increases. A quantum phase transition from a gapless spin_fluid phase to a gapped dimerized phase occurs at a nonzero critical value of the spin_phonon coupling. Our results indicate that the two_particle excitation spectrum is much more sensitive to spin_phonon coupling constant than the one_particle excitation spectrum.

关 键 词：单粒子 束缚态 晶格 激发态 二聚 量子涨落 基态 影响 无能 低能量 

分 类 号：O74[理学—晶体学]