專題演講

2018/02/08(Thu)     10:30 -12:30    5th Floor(1st meeting room)

Title

Violation of Ohm’s law as a hallmark of Weyl metals

Speaker

Prof. Yoon H. Jeong

Dept. of Physics, Pohang Univ of Sci & Tech, Pohang, 37673, Korea

Abstract

Ohm’s law is a fundamental paradigm in the electrical transport of metals. Any transport signatures violating Ohm’s law would give an indisputable fingerprint for a novel metallic state. We uncovered the breakdown of Ohm’s law owing to a topological structure of the chiral anomaly in the Weyl metal phase. We observed nonlinear I–V characteristics in Sb-doped Bi single crystals in the diffusive limit, which occurs only for a magnetic-field-aligned electric field (E || B). We also employed Boltzmann transport theory with the charge pumping effect to reveal the topological-in-origin nonlinear conductivity; the theory yields a universal scaling function of the longitudinal magnetoconductivity, which completely accounts for the experimental results. As a hallmark of Weyl metals, the nonlinear conductivity would provide a venue for nonlinear electronics, optical applications, and the development of a topological Fermi-liquid theory beyond the Landau Fermi-liquid theory.


[1] D. Shin et al, Nature Materials DOI: 10.1038/NMAT4965 (2017). (Paper)