posted on 2022-01-14, 15:35authored byShaosheng Yue, Hui Zhou, Ya Feng, Yue Wang, Zhenyu Sun, Daiyu Geng, Masashi Arita, Shiv Kumar, Kenya Shimada, Peng Cheng, Lan Chen, Yugui Yao, Sheng Meng, Kehui Wu, Baojie Feng
Dirac
materials, which feature Dirac cones in the reciprocal space,
have been one of the hottest topics in condensed matter physics in
the past decade. To date, 2D and 3D Dirac Fermions have been extensively
studied, while their 1D counterparts are rare. Recently, Si nanoribbons
(SiNRs), which are composed of alternating pentagonal Si rings, have
attracted intensive attention. However, the electronic structure and
topological properties of SiNRs are still elusive. Here, by angle-resolved
photoemission spectroscopy, scanning tunneling microscopy/spectroscopy
measurements, first-principles calculations, and tight-binding model
analysis, we demonstrate the existence of 1D Dirac Fermions in SiNRs.
Our theoretical analysis shows that the Dirac cones derive from the
armchairlike Si chain in the center of the nanoribbon and can be described
by the Su–Schrieffer–Heeger model. These results establish
SiNRs as a platform for studying the novel physical properties in
1D Dirac materials.