Chiral anomaly and ultrahigh mobility in crystalline HfTe5

HfTe5 is predicted to be a promising platform for studying topological phases. Here through an electrical transport study, we present an observation of chiral anomaly and ultrahigh mobility in HfTe5 crystals. Negative magnetoresistivity in HfTe5 is observed when the external magnetic and electrical fields are parallel (B//E) and quickly disappears once B deviates from the direction of E. Quantitative fitting further confirms the chiral anomaly as the underlying physics. Moreover, by analyzing the conductivity tensors of longitudinal and Hall traces, ultrahigh mobility and ultralow carrier density are revealed in HfTe5, which paves the way for potential electronic applications.National Basic Research Program of China [2013CB934600, 2012CB921300, 2013CB921900]; Open Project Program of the Pulsed High Magnetic Field Facility, Huazhong University of Science and Technology [PHMFF2015002]; NSF [DMR 1410428]SCI(E)ARTICLEjianwangphysics@pku.edu.cn169