Heat transport of cuprate-based low-dimensional quantum magnets with strong exchange coupling
Heat transport of cuprate-based low-dimensional quantum magnets with strong exchange coupling
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DOI：
10.1016/j.physrep.2019.02.004
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发表时间：
2018-05
期刊：
影响因子：
--
通讯作者：
C. Hess
中科院分区：
文献类型：
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作者：
C. Hess
输运特性为了解固体的准粒子提供了重要途径，例如准粒子密度、迁移率和散射。热量的传递尤其具有启发意义，因为原则上，固体中所有类型的激发都可能有所贡献。声子和电子的热传递已被很好地理解，但对于磁激励传递的热知之甚少。然而，在过去大约二十年中，在低维量子磁性铜酸盐材料中发现磁热传输的巨大且不寻常的特征后，磁热传输引起了越来越多的关注。如今，它成为了对更广泛的量子磁体中难以捉摸的拓扑准粒子的重要探测器。这篇综述总结了这项研究的实验基础，即上述铜酸盐材料中磁热传输的最新技术，该材料具有典型的低维反铁磁 S= 1∕ 2 海森堡模型。这些特别包括二维方晶格、一维自旋链和两腿梯子自旋模型。结果表明，研究热传输如何提供直接了解热占据和这些模型中已经相当奇特的准粒子的散射的方法，这些模型的范围从自旋 1 自旋波和三重子激发到分段自旋 1/2 自旋子。这些准粒子的显着输运特性已被揭示：自旋热输运通常非常高效，在某些情况下甚至是弹道式的，与理论预测一致。
Transport properties provide important access to a solid’s quasiparticles, such as quasiparticle density, mobility, and scattering. The transport of heat can be particularly revealing because, in principle, all types of excitations in a solid may contribute. Heat transport is well understood for phonons and electrons, but relatively little is known about heat transported by magnetic excitations. However, during the last about two decades, the magnetic heat transport attracted increasing attention after the discovery of large and unusual signatures of it in low-dimensional quantum magnetic cuprate materials. Today it constitutes an important probe to otherwise often elusive, topological quasiparticles in a broader class of quantum magnets. This review summarizes the experimental foundation of this research, ie the state of the art for the magnetic heat transport in the mentioned cuprate materials which host prototypical low-dimensional antiferromagnetic S= 1∕ 2 Heisenberg models. These comprise, in particular, the two-dimensional square lattice, and one-dimensional spin chain and two-leg ladder spin models. It is shown, how studying the heat transport provides direct access to the thermal occupation and the scattering of the already quite exotic quasiparticles of these models which range from spin-1 spin wave and triplon excitations to fractionalized spin-1/2 spinons. Remarkable transport properties of these quasiparticles have been revealed: the spin-heat transport often is highly efficient and in some cases even ballistic, in agreement with theoretical predictions.