Origin of the quasi-quantized Hall effect in ZrTe5

TL;DR

This study demonstrates that the quasi-quantized Hall effect observed in ZrTe5 is an intrinsic 3D phenomenon, challenging the traditional view of the quantum Hall effect as purely two-dimensional.

Contribution

The paper provides thermodynamic and transport evidence showing the 3D origin of the QHE in ZrTe5, without Fermi surface instability, supported by theoretical modeling.

Findings

No signatures of Fermi surface instability in thermodynamic measurements

The Hall response is an intrinsic property of the 3D electronic structure

The Hall effect in ZrTe5 is a true 3D counterpart of the 2D QHE

Abstract

The quantum Hall effect (QHE) is traditionally considered a purely two-dimensional (2D) phenomenon. Recently, a three-dimensional (3D) version of the QHE has been reported in the Dirac semimetal ZrTe5. It was proposed to arise from a magnetic-field-driven Fermi surface instability, transforming the original 3D electron system into a stack of 2D sheets. Here, we report thermodynamic, thermoelectric and charge transport measurements on ZrTe5 in the quantum Hall regime. The measured thermodynamic properties: magnetization and ultrasound propagation, show no signatures of a Fermi surface instability, consistent with in-field single crystal X-ray diffraction. Instead, a direct comparison of the experimental data with linear response calculations based on an effective 3D Dirac Hamiltonian suggests that the quasi-quantization of the observed Hall response is an intrinsic property of the 3D electronic structure. Our findings render the Hall effect in ZrTe5 a truly 3D counterpart of the QHE in 2D systems.