Unusual Thermal Hall Effect in a Kitaev Spin Liquid Candidate α-RuCl3
Unusual Thermal Hall Effect in a Kitaev Spin Liquid Candidate α-RuCl3
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DOI：
10.1103/physrevlett.120.217205
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发表时间：
2018-05-25
影响因子：
8.6
通讯作者：
Matsuda, Y.
中科院分区：
文献类型：
--
作者：
Kasahara, Y.;Sugii, K.;Matsuda, Y.
Kitaev量子自旋液体显示了量子自旋到Majorana费米子的分馏。新出现的Majorana边缘电流预计将以有限热霍尔效应的形式表现出来，这是拓扑超导体中经常讨论的一个特征。在这里，我们报道了具有二维蜂窝晶格的候选Kitaev磁体α-RuCl3的热霍尔电导率kappa(Xy)测量。在温度低于类似于80K的Kitaev相互作用J(K)/k(B)的自旋-液体(Kitaev顺磁)状态下，冷却后逐渐形成正卡帕(XY)，这表明存在非常不寻常的巡回激发。尽管零温性质被T-N=7K时的磁有序所掩盖，但kappa(Xy)/T在中温时的符号、大小和T依赖关系遵循巡回Majorana激发的预测趋势。
The Kitaev quantum spin liquid displays the fractionalization of quantum spins into Majorana fermions. The emergent Majorana edge current is predicted to manifest itself in the form of a finite thermal Hall effect, a feature commonly discussed in topological superconductors. Here we report on thermal Hall conductivity kappa(xy) measurements in alpha-RuCl3, a candidate Kitaev magnet with the two-dimensional honeycomb lattice. In a spin-liquid (Kitaev paramagnetic) state below the temperature characterized by the Kitaev interaction J(K)/k(B) similar to 80 K, positive kappa(xy) develops gradually upon cooling, demonstrating the presence of highly unusual itinerant excitations. Although the zero-temperature property is masked by the magnetic ordering at T-N = 7 K, the sign, magnitude, and T dependence of kappa(xy)/T at intermediate temperatures follows the predicted trend of the itinerant Majorana excitations.