Signatures of Temperature-Driven Lifshitz Transition in Semimetal Hafnium Ditelluride

Temperature-driven change of Fermi surface has been attracting attention recently as it is fundamental and essential to understand a metallic system.We report the magnetotransport anomalies in the semimetal HfTe_(2) single crystals.The magnetoresistance behavior at high temperatures obeys Kohler's rule which can lead to the field-induced resistivity upturn behavior as observed.When the temperature is decreased to around 30 K,Kohler's rule becomes inapplicable,indicating the change of the Fermi surface in HfTe_(2).The Hall analyses and extended Kohler's plot reveal abrupt change of carrier densities and mobilities near 30 K.These results suggest that the chemical potential may shift as the temperature increases and the shift causes an electron pocket to vanish.Our work of the temperature-driven Lifshitz transition in HfTe_(2) is relevant to understanding of the transport anomalies and exotic physical properties in transition-metal dichalcogenides.