Figure 4. Observation of weak topological insulator feature in some ZrTe₅ samples.

(a) Cleaved surface morphology of some thin ZrTe₅ samples or thin ZrTe₅ samples after temperature cycling. There are one-dimensional thread-like structures running along the a axis. The additional features presented here are taken on this kind of samples. The scale bar in this panel represents 1 mm. (b,c) Constant energy contours of ZrTe₅ measured around 15 K at binding energy of 0 and 50 meV, respectively. Besides the tiny pocket near the Γ point, there are two nearly one-dimensional spectral streaks on both sides of Γ point running along Γ–Y direction. Band structures measured along momentum cuts 1, 2, 3 and 4 are shown in e. The locations of these momentum cuts are indicated in b. Corresponding MDCs at Fermi level for band structures in e are shown in d. In addition to the usual bands observed in ZrTe₅ as shown in Fig. 1i–l, addition bands are observed here that are marked by the arrows in e.