Identification of nuclear relaxation processes in a gapped quantum magnet: H-1 NMR in the S=1/2 Heisenberg ladder Cu-2(C5H12N2)(2)Cl-4
Identification of nuclear relaxation processes in a gapped quantum magnet: H-1 NMR in the S=1/2 Heisenberg ladder Cu-2(C5H12N2)(2)Cl-4
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DOI：
10.1103/physrevlett.79.925
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发表时间：
1997-08-04
影响因子：
8.6
通讯作者：
Piovesana, O
中科院分区：
文献类型：
--
作者：
Chaboussant, G;Julien, MH;Piovesana, O
测量了S = 12海森堡反铁磁梯形化合物Cu-2（C_5H_（12）N_2）（2）Cl-4的H ~（-1）超精细位移K和NMR弛豫速率T ~（-1）随温度的变化. K和T-1（-1）的结果支持了在这个强耦合阶梯中存在类似或等于J（垂直于）- J（平行于）的自旋能隙Delta（J（（平行于）< J（垂直于））。通过比较两个不同H-1位置的T-1（-1），我们推断了谱函数S-z（q，omega（n））和S-垂直于（q，omega（n））的演化.当差距显着减少的磁场，两个不同的渠道的核弛豫，具体到有间隙的反铁磁体，被确定，并与理论预测一致。
The H-1 hyperfine shift K and NMR relaxation rate T-1(-1) have been measured as a function of temperature in the S = 1/2 Heisenberg antiferromagnetic ladder compound Cu-2(C5H12N2)(2)Cl-4. The presence of a spin gap Delta similar or equal to J(perpendicular to) - J(parallel to) in this strongly coupled ladder (J((parallel to)) < J(perpendicular to)) is supported by the K and T-1(-1) results. By comparing T-1(-1) at two different H-1 sites, we infer the evolution of the spectral functions S-z(q,omega(n)) and S-perpendicular to(q,omega(n)). When the gap is significantly reduced by the magnetic field, two different channels of nuclear relaxation, specific to gapped antiferromagnets, are identified and are in agreement with theoretical predictions.