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arXiv · 2404.13969

Importance of the semimetallic state for the quantum Hall effect in HfTe$_{5}$

M. M. Piva·R. Wawrzyńczak·Nitesh Kumar·L. O. Kutelak·G. A. Lombardi·R. D. dos Reis·C. Felser·M. Nicklas
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Abstract

At ambient pressure, HfTe$_{5}$ is a material at the boundary between a weak and a strong topological phase, which can be tuned by changes in its crystalline structure or by the application of high magnetic fields. It exhibits a Lifshitz transition upon cooling, and three-dimensional (3D) quantum Hall effect (QHE) plateaus can be observed at low temperatures. Here, we have investigated the electrical transport properties of HfTe$_{5}$ under hydrostatic pressure up to 3 GPa. We find a pressure-induced crossover from a semimetallic phase at low pressures to an insulating phase at about 1.5 GPa. Our data suggest the presence of a pressure-induced Lifshitz transition at low temperatures within the insulating phase around 2 GPa. The quasi-3D QHE is confined to the low-pressure region in the semimetallic phase. This reveals the importance of the semimetallic groundstate for the emergence of the QHE in HfTe$_{5}$ and thus favors a scenario based on a low carrier density metal in the quantum limit for the observed signatures of the quasi-quantized 3D QHE.

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M. M. Piva, R. Wawrzyńczak, Nitesh Kumar, L. O. Kutelak, G. A. Lombardi, R. D. dos Reis, C. Felser, M. Nicklas. 2024-04-22. Importance of the semimetallic state for the quantum Hall effect in HfTe$_{5}$. https://doi.org/10.1103/physrevmaterials.8.l041202

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