Unconventional Spectral Gaps Induced by Charge Density Waves in the Weyl Semimetal (TaSe₄)₂I

Coupling between charge density waves (CDWs) and Weyl quasi-particles may lead to gap opening at the Weyl nodes, resulting in intriguing band renormalization and many-body effects. The quasi-one-dimensional chiral compound (TaSe₄)₂I is a candidate that may host CDW-Weyl coupling. If this feature exists, it could be directly identified through photoemission band mapping. However, a strong suppression of spectral weight around the Fermi level hinders the observation of any possible gap opening, making the existence of CDW-Weyl coupling controversial thus far. In this study, we present detailed band mappings of (TaSe₄)₂I. Our photoemission results indicate that, despite a significant suppression of photoemission signals around the Fermi level below the CDW transition temperature, the band dispersions remain unchanged, showing no evidence of gap opening at the Weyl nodes. This suggests the absence of Peierls or axion gaps. Our findings indicate that the unconventional evolution of the band structure arises from quasi-particle localization caused by incommensurate CDW modulations.