Extended Data Fig. 1: (TaSe4)2I crystal structure, growth, device and transport characterization.
From: Axionic charge-density wave in the Weyl semimetal (TaSe4)2I
a, Crystal structure of (TaSe4)2I. b, Sketch of the growth principle. A temperature gradient (temperatures T1 > T2) is imposed on an evacuated quartz ampule, which contains (TaSe4)2I powder at T1. The evaporated (TaSe4)2I diffuses towards the area with temperature T2 and condenses into single crystals. c, Optical micrograph of the as-grown (TaSe4)2I crystals. d, Distribution of Weyl points in momentum (k) space of chirality ±χ. e, Scanning electron microscope image of a crystal. f, Typical device used for electrical-transport measurements. g, h, Single-particle resistance of samples B, C, D and E. The electrical resistance R, normalized by R0 = R(300 K) (g) and its logarithmic derivative (h) as a function of T−1, where T is the temperature. i, Single-particle gaps of all (TaSe4)2I samples investigated. The error denotes the fitting error of 1σ. The dotted line displays the mean value of all samples.
