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arXiv · 2112.10857

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

Zengle Huang·Hemian Yi·Lujin Min·Zhiqiang Mao·Cui-Zu Chang·Weida Wu
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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.

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Zengle Huang, Hemian Yi, Lujin Min, Zhiqiang Mao, Cui-Zu Chang, Weida Wu. 2021-12-20. Absence of in-gap modes in charge density wave edge dislocations of the Weyl semimetal (TaSe$_4$)$_2$I. https://doi.org/10.1103/physrevb.104.205138

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