Concept and realization of Kitaev quantum spin liquids
Concept and realization of Kitaev quantum spin liquids
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DOI：
10.1038/s42254-019-0038-2
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发表时间：
2019-04
影响因子：
38.5
通讯作者：
H. Takagi;T. Takayama;G. Jackeli;G. Khaliullin;S. Nagler
中科院分区：
文献类型：
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作者：
H. Takagi;T. Takayama;G. Jackeli;G. Khaliullin;S. Nagler
十年前，Alexei Kitaev在二维蜂窝晶格上提出了一个精确可解的= 1/2模型，其中自旋分解为Majorana费米子，并在基态形成拓扑量子自旋液体（QSL）。人们很快就认识到，由于电子关联和自旋轨道耦合的相互作用，具有蜂窝结构的复杂铱氧化物和氯化钌家族是磁性绝缘体，并容纳了Kitaev模型的基本成分。这引发了一场竞赛，以实现Kitaev QSL和捕获马约拉纳费米子的签名。在这篇综述中，我们提供了一个广泛的视角，这一迅速发展的领域，包括理论，材料和实验。我们首先总结了Kitaev QSL基态的理论背景和它的物质化使用自旋轨道纠缠= 1/2的时刻。其次是候选材料和它们的磁性的概述，包括NaIrO，-LiIrO，-RuCland HLiIrO。最后，我们回顾了Kitaev QSL搜索的最新令人兴奋的进展。特别是，HLiIrO和RuClin施加的磁场显示的QSL状态的签名，和RuCl具有不寻常的磁激发和热输运性质，是符合自旋分馏。
A decade ago, Alexei Kitaev proposed an exactly solvable= 1/2 model on a two-dimensional honeycomb lattice, where the spins fractionalize into Majorana fermions and form a topological quantum spin liquid (QSL) in the ground state. It was soon recognized that a family of complex iridium oxides, as well as ruthenium chloride, with honeycomb structure are magnetic insulators and accommodate essential ingredients of the Kitaev model, due to the interplay of electron correlation and spin-orbit coupling. This initiated a race to materialize the Kitaev QSL and to capture the signature of Majorana fermions. In this review, we provide a wide perspective of this rapidly growing field, including theory, materials and experiment. We first summarize the theoretical background of the Kitaev QSL ground state and its materialization using spin-orbital-entangled= 1/2 moments. This is followed by an overview of candidate materials and their magnetic properties, including NaIrO,,,-LiIrO,-RuCland HLiIrO. Finally, we review the latest exciting progress in the search for the Kitaev QSL. In particular, HLiIrOand-RuClin applied magnetic field show signatures of the QSL state, and-RuClhas unusual magnetic excitations and thermal transport properties that are consistent with spin fractionalization.