Regular-triangle trimer and charge order preserving the Anderson condition in the pyrochlore structure of CsW2O6
Regular-triangle trimer and charge order preserving the Anderson condition in the pyrochlore structure of CsW2O6
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DOI：
10.1038/s41467-020-16873-7
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发表时间：
2020-06
影响因子：
16.6
通讯作者：
Y. Okamoto;Haruki Amano;N. Katayama;H. Sawa;Kenta Niki;Rikuto Mitoka;H. Harima;T. Hasegawa;N. Ogita;Yukio Tanaka;M. Takigawa;Y. Yokoyama;K. Takehana;Y. Imanaka;Yuto Nakamura;H. Kishida;K. Takenaka
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文献类型：
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作者：
Y. Okamoto;Haruki Amano;N. Katayama;H. Sawa;Kenta Niki;Rikuto Mitoka;H. Harima;T. Hasegawa;N. Ogita;Yukio Tanaka;M. Takigawa;Y. Yokoyama;K. Takehana;Y. Imanaka;Yuto Nakamura;H. Kishida;K. Takenaka
自从在磁铁矿中发现Verwey相变以来，具有烧绿石结构的过渡金属化合物作为实现显着电子相变的平台而被广泛研究。我们报告了保持β-烧绿石氧化物CsW 2 O 6立方对称性的相变，其中每个W 5d电子都被限制在正三角形W3三聚体中。这种三聚体的形成代表了5d电子的自组织，它可以被分解成满足安德森条件的电荷顺序，在一个非平凡的方式，轨道秩序所造成的扭曲WO 6八面体，并形成一个自旋单重态对在一个正三角形三聚体。由于不寻常的三维嵌套的费米面和5d电子的烧绿石氧化物的特性的强相关性的电子不稳定性都可能在这种电荷-轨道-自旋耦合现象中发挥重要作用。
Since the discovery of the Verwey transition in magnetite, transition metal compounds with pyrochlore structures have been intensively studied as a platform for realizing remarkable electronic phase transitions. We report on a phase transition that preserves the cubic symmetry of the β-pyrochlore oxide CsW2O6, where each of W 5delectrons are confined in regular-triangle W3trimers. This trimer formation represents the self-organization of 5delectrons, which can be resolved into a charge order satisfying the Anderson condition in a nontrivial way, orbital order caused by the distortion of WO6octahedra, and the formation of a spin-singlet pair in a regular-triangle trimer. An electronic instability due to the unusual three-dimensional nesting of Fermi surfaces and the strong correlations of the 5delectrons characteristic of the pyrochlore oxides are both likely to play important roles in this charge-orbital-spin coupled phenomenon.