織りなす：カゴメの素材が織りなす電荷と磁気の関係(Interwoven: Charge and magnetism intertwine in kagome material)

伝統的な籠の編み目と結晶の模様が一致する新しい物理現象を発見 New physics discovered where crystal patterns match weave of traditional baskets

2022-09-14 ライス大学

＜関連情報＞

• https://news.rice.edu/news/2022/interwoven-charge-and-magnetism-intertwine-kagome-material
• https://www.nature.com/articles/s41586-022-05034-z

カゴメ格子反強磁性体における電荷密度波の発見 Discovery of charge density wave in a kagome lattice antiferromagnet

Xiaokun Teng,Lebing Chen,Feng Ye,Elliott Rosenberg,Zhaoyu Liu,Jia-Xin Yin,Yu-Xiao Jiang,Ji Seop Oh,M. Zahid Hasan,Kelly J. Neubauer,Bin Gao,Yaofeng Xie,Makoto Hashimoto,Donghui Lu,Chris Jozwiak,Aaron Bostwick,Eli Rotenberg,Robert J. Birgeneau,Jiun-Haw Chu,Ming Yi & Pengcheng Dai
Nature  Published:14 September 2022
DOI:https://doi.org/10.1038/s41586-022-05034-z

Abstract

A hallmark of strongly correlated quantum materials is the rich phase diagram resulting from competing and intertwined phases with nearly degenerate ground-state energies^1,2. A well-known example is the copper oxides, in which a charge density wave (CDW) is ordered well above and strongly coupled to the magnetic order to form spin-charge-separated stripes that compete with superconductivity^1,2. Recently, such rich phase diagrams have also been shown in correlated topological materials. In 2D kagome lattice metals consisting of corner-sharing triangles, the geometry of the lattice can produce flat bands with localized electrons^3,4, non-trivial topology^5,6,7, chiral magnetic order^8,9, superconductivity and CDW order^{10,11,12,13,14,15}. Although CDW has been found in weakly electron-correlated non-magnetic AV₃Sb₅ (A = K, Rb, Cs)^{10,11,12,13,14,15}, it has not yet been observed in correlated magnetic-ordered kagome lattice metals^{4,16,17,18,19,20,21}. Here we report the discovery of CDW in the antiferromagnetic (AFM) ordered phase of kagome lattice FeGe (refs. ^16,17,18,19). The CDW in FeGe occurs at wavevectors identical to that of AV₃Sb₅ (refs. ^{10,11,12,13,14,15}), enhances the AFM ordered moment and induces an emergent anomalous Hall effect^22,23. Our findings suggest that CDW in FeGe arises from the combination of electron-correlations-driven AFM order and van Hove singularities (vHSs)-driven instability possibly associated with a chiral flux phase^{24,25,26,27,28}, in stark contrast to strongly correlated copper oxides^1,2 and nickelates^29,30,31, in which the CDW precedes or accompanies the magnetic order.