A quantum liquid of magnetic octupoles on the pyrochlore lattice
A quantum liquid of magnetic octupoles on the pyrochlore lattice
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DOI：
10.1038/s41567-020-0827-7
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发表时间：
2019-12
期刊：
影响因子：
19.6
通讯作者：
R. Sibille;N. Gauthier;E. Lhotel;V. Porée;V. Pomjakushin;R. Ewings;T. Perring;J. Ollivier;A. Wildes;C. Ritter;T. Hansen;D. Keen;G. Nilsen;L. Keller;S. Petit;T. Fennell
中科院分区：
文献类型：
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作者：
R. Sibille;N. Gauthier;E. Lhotel;V. Porée;V. Pomjakushin;R. Ewings;T. Perring;J. Ollivier;A. Wildes;C. Ritter;T. Hansen;D. Keen;G. Nilsen;L. Keller;S. Petit;T. Fennell
自旋液体是由磁偶极子的纠缠所形成的高度关联但无序的状态。理论定义这样的状态使用规范场和非限定准粒子激发，出现从一个本地约束管理的基态的挫折磁铁。例如，四面体上偶极矩的“2进2出”冰规则可以导致量子自旋冰，-在稀土火辉石中。然而，f-电子离子通常具有比偶极子更高的自由度，导致有趣的行为和“隐藏”的订单。在这里，我们表明，相关的基态Ce 3+基烧绿石，Ce 2Sn 2 O 7，是一个磁八极子的量子液体。我们的中子散射结果是一致的流体状的状态，自由度有一个更复杂的磁化强度比磁偶极子。八极-八极耦合的性质和强度，加上自旋子激发的连续性，为八极的量子冰受“2加2减”规则支配提供了进一步的证据。我们的工作确定Ce 2Sn 2 O 7作为一个独特的例子，挫折多极形成一个“隐藏”的拓扑秩序，从而概括观察量子自旋液体多极相，可以支持新类型的新兴领域和激发。
Spin liquids are highly correlated yet disordered states formed by the entanglement of magnetic dipoles. Theories define such states using gauge fields and deconfined quasiparticle excitations that emerge from a local constraint governing the ground state of a frustrated magnet. For example, the ‘2-in–2-out’ ice rule for dipole moments on a tetrahedron can lead to a quantum spin ice, –in rare-earth pyrochlores. However,f-electron ions often carry multipole degrees of freedom of higher rank than dipoles, leading to intriguing behaviours and ‘hidden’ orders,. Here we show that the correlated ground state of a Ce3+-based pyrochlore, Ce2Sn2O7, is a quantum liquid of magnetic octupoles. Our neutron scattering results are consistent with a fluid-like state where degrees of freedom have a more complex magnetization density than that of magnetic dipoles. The nature and strength of the octupole–octupole couplings, together with the existence of a continuum of excitations attributed to spinons, provides further evidence for a quantum ice of octupoles governed by a ‘2-plus–2-minus’ rule,. Our work identifies Ce2Sn2O7as a unique example of frustrated multipoles forming a ‘hidden’ topological order, thus generalizing observations on quantum spin liquids to multipolar phases that can support novel types of emergent fields and excitations.