Excitations in the field-induced quantum spin liquid state of α-RuCl3
Excitations in the field-induced quantum spin liquid state of α-RuCl3
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DOI：
10.1038/s41535-018-0079-2
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发表时间：
2018-02-20
影响因子：
5.7
通讯作者：
Nagler, Stephen E.
中科院分区：
文献类型：
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作者：
Banerjee, Arnab;Lampen-Kelley, Paula;Nagler, Stephen E.
著名的Kitaev量子自旋液体（QSL）是拓扑磁体的典型例子，它具有马约拉纳费米子和规范通量形式的涌现激发。当时间反演对称性被打破时，例如在外部磁场中，这些分形准粒子获得非阿贝尔交换统计，这是拓扑保护量子计算的重要组成部分。因此，人们对探索Kitaev物理学的可能材料实现产生了极大的兴趣，并提出了几种候选材料，最近包括α-RuCl 3。在没有磁场的情况下，这种材料在有限的温度下有序，并表现出低能量的自旋波激发。然而，在中等能量下，光谱是非常规的，并且响应显示分数激发的证据。在这里，我们使用飞行时间的非弹性中子散射表明，在蜂窝状平面中的足够大的磁场的应用程序抑制磁秩序和自旋波，留下一个缺口的连续谱的磁激发。我们的散射的Kitaev QSL的可用计算的比较表明，它们是一致的磁场诱导QSL相位。
The celebrated Kitaev quantum spin liquid (QSL) is the paradigmatic example of a topological magnet with emergent excitations in the form of Majorana Fermions and gauge fluxes. Upon breaking of time-reversal symmetry, for example in an external magnetic field, these fractionalized quasiparticles acquire non-Abelian exchange statistics, an important ingredient for topologically protected quantum computing. Consequently, there has been enormous interest in exploring possible material realizations of Kitaev physics and several candidate materials have been put forward, recently including alpha-RuCl3. In the absence of a magnetic field this material orders at a finite temperature and exhibits low-energy spin wave excitations. However, at moderate energies, the spectrum is unconventional and the response shows evidence for fractional excitations. Here we use time-of-flight inelastic neutron scattering to show that the application of a sufficiently large magnetic field in the honeycomb plane suppresses the magnetic order and the spin waves, leaving a gapped continuum spectrum of magnetic excitations. Our comparisons of the scattering to the available calculations for a Kitaev QSL show that they are consistent with the magnetic field induced QSL phase.