Phase Transitions in Quasi-One-Dimensional (TaSe₄)₂I Weyl Semimetal Nanoribbons Revealed with Electronic Noise Spectroscopy

We investigated low-frequency current fluctuations, also referred to as excess noise, in quasi-one-dimensional (TaSe₄)₂I Weyl semimetal nanoribbons. It was found that the noise spectral density is of the 1/f type and scales with the square of the current (f is the frequency). The noise spectral density increases by almost an order of magnitude and develops Lorentzian features near the temperature T~225 K. These spectral changes were attributed to the charge-density-wave phase transition. The noise level, normalized by the channel area, in these Weyl semimetal nanoribbons was surprisingly low when measured below and above the Peierls transition temperature. We studied the noise scaling with the cross-sectional area of the Weyl semimetal nanoribbons. The nature of the phase transition that shows non-metallic behavior below and above the transition point will be discussed. Obtained results shed light on the specifics of electron transport in quasi-1D topological Weyl semimetals and can be useful for their proposed applications as downscaled interconnects.