Author(s): Zheng, XH (Zheng, Xiaohu); Gu, QQ (Gu, Qiangqiang); Liu, YY (Liu, Yiyuan); Tong, BB (Tong, Bingbing); Zhang, JF (Zhang, Jian-Feng); Zhang, C (Zhang, Chi); Jia, S (Jia, Shuang); Feng, J (Feng, Ji); Du, RR (Du, Rui-Rui)

Source: NATIONAL SCIENCE REVIEW Volume: 9 Issue: 8 Article Number: nwab191 DOI: 10.1093/nsr/nwab191 Published: SEP 12 2022

Abstract: Scanning-tunneling spectroscopy reveals signature of Fermi arcs at 1D ledges on a Weyl semimetal's surfaces, demonstrating that the principle of bulk-boundary correspondence works even down to atomic scales.

Fermi arcs on Weyl semimetals exhibit many exotic quantum phenomena. Usually found on atomically flat surfaces with approximate translation symmetry, Fermi arcs are rooted in the peculiar topology of bulk Bloch bands of 3D crystals. The fundamental question of whether a 1D Fermi arc can be probed remains unanswered. Such an answer could significantly broaden potential applications of Weyl semimetals. Here, we report a direct observation of robust edge states on atomic-scale ledges in TaAs using low-temperature scanning tunneling microscopy/spectroscopy. Spectroscopic signatures and theoretical calculations reveal that the 1D Fermi arcs arise from the chiral Weyl points of bulk crystals. The crossover from 2D Fermi arcs to eventual complete localization on 1D edges was arrested experimentally on a sequence of surfaces. Our results demonstrate extreme robustness of the bulk-boundary correspondence, which offers topological protection for Fermi arcs, even in cases in which the boundaries are at the atomic-scale. The persistent 1D Fermi arcs can be profitably exploited in miniaturized quantum devices.

Accession Number: WOS:000852784800001

PubMed ID: 36105944

ISSN: 2095-5138

eISSN: 2053-714X

Full Text: https://academic.oup.com/nsr/article/9/8/nwab191/6409843