Quantized plateau in the thermoelectric Hall conductivity for Dirac electrons in the extreme quantum limit
Open Access Publications from the University of California

## Quantized plateau in the thermoelectric Hall conductivity for Dirac electrons in the extreme quantum limit

• Author(s): Zhang, Wenjie
• Wang, Peipei
• Skinner, Brian
• Bi, Ran
• Cho, Chang-Woo
• Zhong, Ruidan
• Schneeloch, John
• Yu, Dapeng
• Gu, Genda
• Fu, Liang
• Wu, Xiaosong
• Zhang, Liyuan
• et al.
Abstract

When subjected to a sufficiently strong magnetic field, the properties of electronic quantum matter change dramatically. This is especially true in the "extreme quantum limit" (EQL), in which the spacing between quantized energy levels of the electron cyclotron motion becomes larger than any other relevant energy scale. Here we probe deeply into the EQL in the three-dimensional Dirac semimetal ZrTe$_5$. We measure the bulk thermoelectric properties, and we find them to be greatly enhanced over their zero-field values. Most strikingly, the thermoelectric Hall conductivity $\alpha_{xy}$ acquires a universal, quantized value deep in the EQL, which is independent of magnetic field or carrier concentration. We explain this quantization theoretically and show how it is a unique signature of three-dimensional Dirac or Weyl electrons in the EQL.