Park Jae Whan, Cho Gil Young, Lee Jinwon, Yeom Han Woong
Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang, 790-784, Korea.
Department of Physics, Pohang University of Science and Technology, Pohang, 790-784, Korea.
Nat Commun. 2019 Sep 6;10(1):4038. doi: 10.1038/s41467-019-11981-5.
When two periodic potentials compete in materials, one may adopt the other, which straightforwardly generates topological defects. Of particular interest are domain walls in charge-, dipole-, and spin-ordered systems, which govern macroscopic properties and important functionality. However, detailed atomic and electronic structures of domain walls have often been uncertain and the microscopic mechanism of their functionality has been elusive. Here, we clarify the complete atomic and electronic structures of the domain wall network, a honeycomb network connected by Z vortices, in the nearly commensurate Mott charge-density wave (CDW) phase of 1T-TaS. Scanning tunneling microscopy resolves characteristic charge orders within domain walls and their vortices. Density functional theory calculations disclose their unique atomic relaxations and the metallic in-gap states confined tightly therein. A generic theory is constructed, which connects this emergent honeycomb network of conducting electrons to the enhanced superconductivity.
当两种周期性势在材料中相互竞争时，一种可能会采用另一种，这直接产生了拓扑缺陷。特别令人感兴趣的是电荷、偶极子和自旋有序系统中的畴壁，它们决定了宏观性质和重要功能。然而，畴壁的详细原子和电子结构常常不确定，其功能的微观机制也难以捉摸。在这里，我们阐明了在1T-TaS的近 commensurate 莫特电荷密度波（CDW）相中，由Z涡旋连接的蜂窝状网络——畴壁网络的完整原子和电子结构。扫描隧道显微镜解析了畴壁及其涡旋内的特征电荷序。密度泛函理论计算揭示了它们独特的原子弛豫以及紧密限制在其中的金属能隙态。构建了一个通用理论，将这种新兴的导电电子蜂窝状网络与增强的超导性联系起来。
