Institut Néel CNRS, Université Grenoble Alpes, 38042, Grenoble, France.
Laboratoire Léon Brillouin, CEA CNRS Université Paris Saclay, CE-Saclay, 91191, Gif-sur-Yvette, France.
Nat Commun. 2018 Sep 17;9(1):3786. doi: 10.1038/s41467-018-06212-2.
The search for two-dimensional quantum spin liquids, exotic magnetic states remaining disordered down to zero temperature, has been a great challenge in frustrated magnetism over the last few decades. Recently, evidence for fractionalized excitations, called spinons, emerging from these states has been observed in kagome and triangular antiferromagnets. In contrast, quantum ferromagnetic spin liquids in two dimensions, namely quantum kagome ices, have been less investigated, yet their classical counterparts exhibit amazing properties, magnetic monopole crystals as well as magnetic fragmentation. Here, we show that applying a magnetic field to the pyrochlore oxide NdZrO, which has been shown to develop three-dimensional quantum magnetic fragmentation in zero field, results in a dimensional reduction, creating a dynamic kagome ice state: the spin excitation spectrum determined by neutron scattering encompasses a flat mode with a six arm shape akin to the kagome ice structure factor, from which dispersive branches emerge.
在过去的几十年里，寻找二维量子自旋液体一直是受挫磁体领域的一大挑战，这种奇特的磁态在零温度下仍然保持无序。最近，在 kagome 和三角反铁磁体中观察到了这些态中出现的分数激发，称为自旋子。相比之下，二维量子铁磁自旋液体，即量子 kagome 冰，研究得较少，但它们的经典对应物表现出令人惊讶的性质，如磁单晶体以及磁碎化。在这里，我们表明，在已被证明在零场中发展出三维量子磁碎化的 pyrochlore 氧化物 NdZrO 中施加磁场会导致维度降低，从而产生动态 kagome 冰态：通过中子散射确定的自旋激发谱包含一个具有六臂形状的扁平模式，类似于 kagome 冰结构因子，从中出现色散分支。
