Absence of in-gap modes in charge density wave edge dislocations of the Weyl semimetal (TaSe${}_4$)${}_2$I

Abstract

Axion electrodynamics in condensed matter could emerge from the formation of charge density waves (CDWs) in Weyl semimetals. (TaSe${}_4$)${}_2$I was proposed to be the first material platform for realizing axionic CDW that may host topological defects with one-dimensional in-gap modes. The real-space modulation of the CDW phase and the existence of in-gap modes remain elusive. Here, we present a comprehensive scanning tunneling microscopic and spectroscopic study of a CDW on a (TaSe${}_4$)${}_2$I (110) surface. The tunneling spectroscopic measurements reveal a CDW gap of $\sim 200$ meV, in good agreement with prior studies, while the spectroscopy of CDW edge dislocation shows no indication of in-gap states. The bias-dependent scanning tunneling microscopy images indicate that the CDW in(TaSe${}_4$)${}_2$I is dominated by a large periodic lattice distortion instead of charge modulation, suggesting a non-Peierls mechanism of the CDW instability.

15 pages, 5 figures

References in corpus (5)

• Theory of Intertwined Orders in High Temperature Superconductors
• Fermi surface nesting and the origin of Charge Density Waves in metals
• Chiral anomaly, Charge Density Waves, and Axion Strings from Weyl Semimetals
• Surface Charge Induced Dirac Band Splitting in a Charge Density Wave Material (TaSe4)2I
• Kramers-Weyl fermions in the chiral charge density wave material (TaSe${}_4$)${}_2$I