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Title: Anomalous high-field magnetotransport in CaFeAsF due to the quantum Hall effect

CaFeAsF is an iron-based superconductor parent compound whose Fermi surface is quasi-two dimensional, composed of Dirac-electron and Schrödinger-hole cylinders elongated along thecaxis. We measured the longitudinal and Hall resistivities in CaFeAsF with the electrical current in theabplane in magnetic fields up to 45 T applied along thecaxis and obtained the corresponding conductivities via tensor inversion. We found that both the longitudinal and Hall conductivities approached zero above ~40 T as the temperature was lowered to 0.4 K. Our analysis indicates that the Landau-level filling factor isν = 2 for both electrons and holes at these high field strengths, resulting in a total filling factorν = νhole − νelectron = 0. We therefore argue that theν = 0 quantum Hall state emerges under these conditions.

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Publication Date:
Journal Name:
npj Quantum Materials
Nature Publishing Group
Sponsoring Org:
National Science Foundation
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