Submillimeter Wave ESR Study of Spin Gap Excitations in CuGeO3
Submillimeter Wave ESR Study of Spin Gap Excitations in CuGeO3
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CuGeO3 中自旋间隙激发的亚毫米波 ESR 研究
DOI：
10.1143/jpsj.68.3417
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发表时间：
1999
影响因子：
1.7
通讯作者：
M. Motokawa
中科院分区：
文献类型：
--
作者：
H. Nojiri;H. Ohta;S. Okubo;O. Fujita;J. Akimitsu;M. Motokawa
利用亚毫米波电子自旋共振技术，在CuGeO 3中观察到基态单重态和激发三重态之间的跃迁。在零场的能隙被评估为570 GHz（2.36 meV），这个值是几乎相同的差距在区中心观察到的非弹性中子散射。吸收强度表现出较强的场取向依赖性，但对磁场强度没有明显的依赖性。这些特征可以通过考虑Dzyaloshinsky-Moriya（DM）反对称交换相互作用的存在来解释。对这种单重-三重激发的掺杂效应也进行了研究。通过仅掺杂0.5%的Si观察到吸收线的急剧加宽。
Transitions between the ground singlet state and the excited triplet state have been observed in CuGeO 3 by means of submillimeter wave electron spin resonance. The energy gap at zero field is evaluated to be 570 GHz (2.36 meV) and this value is nearly identical to the gap at the zone center observed by inelastic neutron scattering. The absorption intensity shows strong field orientation dependence, but it shows no significant dependence on magnetic field intensity. These features have been explained by considering the existence of Dzyaloshinsky-Moriya (DM) antisymmetric exchange interaction. The doping effect on this singlet-triplet excitation has been also studied. A drastic broadening of the absorption line is observed by the doping of only 0.5 % of Si.