Quantum oscillations and stacked quantum Hall effect in HfTe5

Abstract

We report the magneto-transport measurements on bulk HfTe5 with carrier mobility exceeding 100 000 cm2/(V s). The longitudinal resistance anomaly and the sign change in Hall coefficient with temperature are observed, which may be induced by Lifshitz transition. When the magnetic field is applied along the b-axis and a-axis at low temperature, a series of Shubnikov-de Haas oscillations on the longitudinal transport exhibit, demonstrating a three-dimensional Fermi-surface pocket for HfTe5 rather than two-dimensional (2D). The investigations on Landau level fan diagram confirm the existence of the non-trivial πBerry phase. The cyclotron mass m cyc as around 0.02 m e and quantum scattering time τ at about 1.76 ps are also estimated with Lifshitz-Kosevich theory. Further detailed analysis suggests that a stacked quantum Hall effect attributed to multi-parallel 2D conduction layers develops in HfTe5.