High-pressure regulation effects on the magnetotransport properties of flux-grown ZrTe5 single crystals

Flux-grown ZrTe5 crystals with near-ideal stoichiometric composition exhibit semiconducting behavior at ambient pressure, which can be systematically manipulated by altering the Te content or by applying external pressure or magnetic field. In this study, we investigate the electrical resistivity and magnetoresistivity (MR) of flux-grown ZrTe5 single crystals under pressures up to 7 GPa using a palm cubic anvil high-pressure cell. The pressure-dependent electrical resistivity reveals a systematic crossover from a semiconducting to a semimetallic phase between 3 and 4 GPa, which also coincides with the sign reversal of the Hall resistivity at low temperatures. These experimental observations collectively suggest the occurrence of a pressure-induced Lifshitz-like transition in the 3-4 GPa pressure range. Furthermore, at 7 GPa, we observe a sudden drop in electrical resistivity near 3.4 K, indicative of a superconducting transition. Notably, the observed superconducting transition temperature is nearly twice that reported for previously studied chemical vapor transport (CVT)-grown ZrTe5 crystals (Tc ≈ 1.8 K). To gain additional theoretical insight, we also performed first-principles calculations including spin-orbit coupling over a wide 0-6 GPa pressure range. The calculations reveal a substantial reconstruction of the low-energy electronic states, characterized by a pronounced enhancement of the density of states at the Fermi level and a significant modification of the band gap near 3 GPa, consistent with the experimentally observed phenomena. Symmetry-indicator and Wilson-loop analyses were further performed to investigate the evolution of the topological electronic structure under pressure. These findings demonstrate that pressure, together with subtle variations in crystal stoichiometry, drives remarkable electronic and structural transformations in ZrTe5, consistent with the pressure-induced Lifshitz transition and enhanced superconductivity in this Dirac semimetal.