Title: Resistivity anomaly and negative longitudinal magnetoresistance in ZrTe5
Speaker: Dr. Bo Fu , HongKong University
Time: June. 24 (Friday), 10:00
Place: #腾讯会议：158-717-189
             会议密码：0624

Abstract: Demonstrated by the first principles calculation and the angle-resolved photoemission spectroscopy (ARPES) measurement, the transition-metal pentatelluride ZrTe5 is the prototype of massive Dirac material close to the topological critical point. Many exotic and anomalous behaviors of electric and thermoelectric transport were revealed recent years in this system. Resistivity in ZrTe5 exhibits a sharp peak at a finite temperature Tp. The peak occurs approximately at a large range of temperatures from 50 to 200K, but the exact value varies from sample to sample. This resistivity anomaly is always accompanied with the sign change of the Hall and Seebeck coefficients around the transition temperature. We propose a theory of quasiparticles to address a series of anomalous behaviors measured in ZrTe5. The negative longitudinal magnetoresistance in this system was observed in a series of experiments by different groups, and was shown the quadratic behavior of magnetic field. Under pressure, ZrTe5 undergoes a topological phase transition accompanied by the closing and reopening of the band gap. The quadratic coefficient of the magnetoconductivity also varies with the external strain. We propose a quantum magneto-transport theory based on Landau level representation different from the chiral anomaly mechanism to account for the quadratic behavior and the strain dependence of the magnetoconductivity in ZrTe5. 

References:
(1) Bo Fu, Huan-Wen Wang , and Shun-Qing Shen, Dirac Polarons and Resistivity Anomaly in ZrTe5 and HfTe5, PHYSICAL REVIEW LETTERS 125, 256601 (2020).
(2)Bo Fu, Huan-Wen Wang , and Shun-Qing Shen, Quantum magnetotransport in massive Dirac materials, PHYSICAL REVIEW B 101, 125203 (2020).
(3)Huan-Wen Wang , Bo Fu, and Shun-Qing Shen, Helical symmetry breaking and quantum anomaly in massive Dirac fermions, PHYSICAL REVIEW B 104, L241111 (2021).