Mitsuishi N, Sugita Y, Bahramy M S, Kamitani M, Sonobe T, Sakano M, Shimojima T, Takahashi H, Sakai H, Horiba K, Kumigashira H, Taguchi K, Miyamoto K, Okuda T, Ishiwata S, Motome Y, Ishizaka K
Department of Applied Physics, The University of Tokyo, Tokyo, 113-8656, Japan.
Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Wako, 113-8656, Japan.
Nat Commun. 2020 May 18;11(1):2466. doi: 10.1038/s41467-020-16290-w.
Topologically nontrivial materials host protected edge states associated with the bulk band inversion through the bulk-edge correspondence. Manipulating such edge states is highly desired for developing new functions and devices practically using their dissipation-less nature and spin-momentum locking. Here we introduce a transition-metal dichalcogenide VTe, that hosts a charge density wave (CDW) coupled with the band inversion involving V3d and Te5p orbitals. Spin- and angle-resolved photoemission spectroscopy with first-principles calculations reveal the huge anisotropic modification of the bulk electronic structure by the CDW formation, accompanying the selective disappearance of Dirac-type spin-polarized topological surface states that exist in the normal state. Thorough three dimensional investigation of bulk states indicates that the corresponding band inversion at the Brillouin zone boundary dissolves upon the CDW formation, by transforming into anomalous flat bands. Our finding provides a new insight to the topological manipulation of matters by utilizing CDWs' flexible characters to external stimuli.
拓扑非平凡材料通过体边对应关系拥有与体能带反转相关的受保护边缘态。利用这些边缘态无耗散的特性和自旋动量锁定来开发新功能和器件是非常有必要的。在这里，我们介绍一种过渡金属二硫属化物VTe₂，它具有与涉及V 3d和Te 5p轨道的能带反转耦合的电荷密度波（CDW）。结合第一性原理计算的自旋和角分辨光电子能谱揭示了CDW形成对体电子结构的巨大各向异性修饰，同时正常态下存在的狄拉克型自旋极化拓扑表面态选择性消失。对体态的全面三维研究表明，布里渊区边界处相应的能带反转在CDW形成时通过转变为反常平带而消失。我们的发现为利用CDW对外部刺激的灵活特性进行物质的拓扑操纵提供了新的见解。
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