Evidence for an axionic charge density wave in the Weyl semimetal (TaSe4)2I
Abstract
An axion insulator is a correlated topological phase, predicted to arise from the formation of a charge density wave in a Weyl semimetal. The accompanying sliding mode in the charge density wave phase, the phason, is an axion. It is expected to cause anomalous magneto-electric transport effects. However, this axionic charge density wave has so far eluded experimental detection. In this paper, we report the observation of a large, positive contribution to the magneto-conductance in the sliding mode of the charge density wave Weyl semimetal (TaSe4)2I for collinear electric and magnetic fields (E||B). The positive contribution to the magneto-conductance originates from the anomalous axionic contribution of the chiral anomaly to the phason current, and is locked to the parallel alignment of E and B. By rotating B, we show that the angular dependence of the magneto-conductance is consistent with the anomalous transport of an axionic charge density wave.
Keywords
Cite
@article{arxiv.1906.04510,
title = {Evidence for an axionic charge density wave in the Weyl semimetal (TaSe4)2I},
author = {Johannes Gooth and Barry Bradlyn and Shashank Honnali and Clemens Schindler and Nitesh Kumar and Jonathan Noky and Yangpeng Qi and Chandra Shekhar and Yan Sun and Zhijun Wang and Bogdan Andrei Bernevig and Claudia Felser},
journal= {arXiv preprint arXiv:1906.04510},
year = {2019}
}