Kim Hyeonjung, Jin Kyung-Hwan, Yeom Han Woong
Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea.
Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
Nano Lett. 2024 Nov 13;24(45):14323-14328. doi: 10.1021/acs.nanolett.4c03970. Epub 2024 Oct 29.
Domain walls (DWs) have been recognized to play crucial roles in various interesting properties and functionalities in quantum materials. A notable example is DWs in charge density wave (CDW), which are believed to provide metallic electron channels for emerging superconductivity. However, electronic states of DWs and the microscopic mechanism toward superconductivity have been elusive. Here, we clarify the atomic/electronic structure of DWs of the chiral CDW emerging in 1-TiSe, using scanning tunneling microscopy and density functional calculations. We reveal unambiguously the microscopic origin of chiral CDW as the 2 distortion in Se layers and its interlayer coupling. We further identify unique DWs connecting CDW domains of opposite chirality. The DWs are endowed with no in-gap state due to the characteristic multibands around the band gap, which defies the widely believed notion for CDW DWs. These results provide an important insight into the role of DWs in emerging superconductivity.
畴壁(DWs)已被认为在量子材料的各种有趣特性和功能中起着关键作用。一个显著的例子是电荷密度波(CDW)中的畴壁,据信它为新兴的超导性提供金属电子通道。然而,畴壁的电子态以及超导性的微观机制一直难以捉摸。在这里,我们使用扫描隧道显微镜和密度泛函计算,阐明了1-TiSe中出现的手性CDW的畴壁的原子/电子结构。我们明确揭示了手性CDW的微观起源是Se层中的2畸变及其层间耦合。我们进一步识别出连接相反手性的CDW畴的独特畴壁。由于带隙周围的特征多带,这些畴壁没有带隙态,这与广泛认为的CDW畴壁的概念相悖。这些结果为畴壁在新兴超导性中的作用提供了重要见解。