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Study of giant thermal conductivity due to magnons in low-dimensional quantum spin system copper oxides

低维量子自旋体系铜氧化物中磁振子的巨热导率研究

基本信息

批准号：
14340097
负责人：
KOIKE Yoji
金额：
$ 10.88万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

We have studied the thermal conductivity and other physical properties of several copper oxides regarded as low-dimensional quantum spin systems, in order to clarify the mechanism of the giant thermal conductivity due to magnons and also to clarify whether the thermal conductivity measurement is powerful for the detection of a phase transition or not.We have discovered large thermal conductivity due to magnons in the four-leg spin-ladder system La_2Cu_2O_5 and the two-dimensional spin system Cu_3B_2O_6.In one-dimensional spin systems Sr_2CuO_3 and SrCuO_2, we have proved from the study of the impurity effects that the thermal conductivity due to magnons is very large and that the thermal conduction is ballistic as theoretically expected.From these results, it has been concluded that both the large antiferromagnetic interaction between spins and the large dispersion of magnons give rise to the large thermal conductivity due to magnons.Moreover, marked changes of the thermal conductivity have been observed at the following phase transitions; the spin-flop transition in the antiferromagnetically ordered state of Ca_2Y_2Cu_5O_<10> and Cu_3B_2O_6, the Bose-Einstein condensation transition off magnons in TlCuCl_3 under high magnetic fields at low temperatures, and the field-induced magnetic order in La_<2-x>Sr_xCUO_4 and La_<2-x>Ba_xCuO_4. Accordingly, we have concluded that the thermal conductivity measurement is a powerful probe to detect and study a phase transition.

我们研究了几种铜氧化物作为低维量子自旋系统的热导率和其他物理性质，为了阐明磁振子引起的巨大热导率的机制以及热导率测量对相变的探测是否有效，我们在四臂自旋梯系统La_2Cu_3中发现了磁振子引起的巨大热导率。在一维自旋系统Sr_2CuO_3和SrCuO_2中，我们从杂质效应的研究中证明了磁振子引起的热导率很大，并证明了热导是弹道式的。结果表明，自旋之间的强反铁磁相互作用和磁振子的大色散都导致了磁振子的大热导率。此外，在Ca_2Y_2Cu_5O_3和Cu_3B_2O_6的反铁磁有序态中观察到自旋翻转相变<10>，在TlCuCl_3中观察到低温强磁场下磁振子的玻色-爱因斯坦凝聚相变，在La_ Sr_xCuO_4和La_ Ba_xCuO_4中观察到场诱导磁<2-x><2-x>有序相变。因此，我们得出结论，热导率测量是一个强有力的探针来检测和研究相变。

项目成果

期刊论文数量（96）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Single-Crystal Growth and the Dependence on Hole Concentration and Magnetic Field of the Magnetic Ground State in the edge-Sharing CuO2 Chain System Ca2+xY2-xCu5O10

共享边缘 CuO2 链系统 Ca2 xY2-xCu5O10 中单晶生长以及对空穴浓度和磁基态磁场的依赖性

DOI：
发表时间：
2005
期刊：
Phys. Rev. B 71
影响因子：
0
作者：
M.Wakasugi;M.Wakasugi;T.Suda;M.Wakasugi;M.Wakasugi;T.Nishizaki;M.Wakasugi;T.Naito;T.Suda;K.Kudo;須田利美;M.Maki;M.Wakasugi;K.Shibata;T.Suda;K.Kudo
通讯作者：
K.Kudo

Thermal conductivity in low-dimensional quantum spin systems.

低维量子自旋系统中的热导率。

DOI：
发表时间：
2003
期刊：
Solid State Physics[in Japanese] 38
影响因子：
0
作者：
Y.Matsushita;J.Taniguchi;A.Yamaguchi;H.Ishimoto;H.Ikegami;T.Matsushita;N.Wada;S.M.Gatica;M.W.Cole;F.Ancilotto;K.Kudo
通讯作者：
K.Kudo

Thermal conductivity in the Bose-Einstein condendsed state of TlCuCl_3.

TlCuCl_3 玻色-爱因斯坦凝聚态的热导率。