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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 in 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. The speaker and his research group 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 in 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. They 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).

About the Speaker
 

Dr. FU Bo obtained his PhD from the University of Science and Technology of China in June 2017. He then joined the Department of Physics of the University of Hong Kong as a Postdoctoral Fellow.
 

Dr. Fu’s research focuses on the theoretical studies of anomalous transport in topological materials, topological state and the exotic quantum phenomena in the presence of intrinsic interaction and disorder. The main theoretical method he used to study the transport properties is the Feynman diagrammatic technique and topological field theory. He has developed a quantum theory for magneto-transport in massive and massless Dirac materials, which is applicable to the system with either Abelian or non-Abelian Berry curvature. His recent interest is quantum anomaly related phenomena in new topological materials and their electronic transport properties.

About the Center
 

For more information, please refer to the center website at https://iascqt.hkust.edu.hk/.