一维反铁磁海森堡自旋链上spinon的安德森局域化最终报告  

Anderson Localization of Spinons on a One-dimensional Antiferromagnetic Heisenberg Spin Chain

作　　者：李世燕[1] Li Shiyan(Fudan University)

机构地区：[1]复旦大学

出　　处：《科技创新导报》2016年第33期185-186,共2页Science and Technology Innovation Herald

摘　　要：安德森局域化是物理学中的一个基本现象,最初是安德森提出在晶体中电子受到杂质散射由于散射路径的相干导致电导完全消失,这完全来源于电子的波动特性,后来在其他各种波,如,光、微波、超声波,甚至是冷原子体系中都观察到安德森局域化现象。在晶体中,除电子外,还可能存在各种各样的磁激发准粒子,但是对于这些磁性准粒子的安德森局域化研究几乎没有。我们测量了苯甲酸铜Cu(C6H5COO)2·3H2O这个一维反铁磁海森堡链单晶的极低温比热和热导率,发现一直到50 m K的极低温,spinon磁性准粒子对比热都有一个恒定的线性贡献项Cs/T,但是其热导率的线性贡献项ks/T只保持不变到300 m K。在300m K以下,ks/T迅速减小,到100 m K以下就基本消失了。实验结果是spinon安德森局域化的一个较强的证据,为在凝聚态物理中研究安德森局域化现象开辟了一个新的窗口。Anderson localization is a general phenomenon of wave physics,which stems from the interference between multiple scattering paths.It was originally proposed for electrons in a crystal,but later was also observed for light,microwaves,ultrasound,and ultracoldatoms.Actually,in a crystal,besides electrons there may exist other quasiparticles such as magnons and spinons.However the searchfor Anderson localization of these magnetic excitations is very rare so far.Here we report the first observation of spinon localization incopper benzoate,an ideal compound of spin-1/2antiferromagnetic Heisenberg chain,by ultra-low-temperature thermal conductivity andspecific heat measurements.We find that the spinons thermal conductivity ks manifests linear temperature dependence down to300mK.Below300mK,ks/T decreases rapidly and vanishes at about100mK,while the spinon specific heat Cs displays linear temperaturedependence all the way down to50mK.This result is a clear evidence for Anderson localization of spinons in one-dimensional spinchain.Our finding opens a new window for studying such a fundamental phenomenon in condensed matter physics.

关 键 词：反铁磁自旋链 自旋子 热导率 安德森局域化 

分 类 号：O482.525[理学—固体物理]