Observation of one-dimensional Dirac fermions in silicon nanoribbons

TL;DR

This paper reports the experimental and theoretical discovery of one-dimensional Dirac fermions in silicon nanoribbons, revealing their electronic structure and topological properties, and establishing SiNRs as a new platform for 1D Dirac physics.

Contribution

It provides the first observation and analysis of 1D Dirac fermions in silicon nanoribbons, combining experimental techniques and theoretical models.

Findings

Existence of 1D Dirac cones in SiNRs confirmed

Dirac cones originate from armchair-like Si chains

Topological properties described by Su-Schrieffer-Heeger model

Abstract

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.