Tuning the Topological Phases of ZrTe5 Single Crystals by Uniaxial Stress

ZrTe5 has been theoretically predicted to be a quantum spin Hall insulator in single layer form. In bulk form, the calculation suggested that ZrTe5 resides near a phase transition between a strong and weak topological insulator (TI), and the exact location sensitively depends on the lattice constants. Here, we report a systematic investigation that combines electrical transport measurements and DFT calculations on the effect of uniaxial stress along the crystalline a-axis. We have observed a non-monotonic, temperature dependent resistance-strain relationship. The DFT calculations also reveal a closing and opening of the energy gap as a function of uniaxial strain. The implications of this observation with respect to the existence of a strain induced topological phase transition will be discussed.