%ATerashima, Taichi%AHirose, Hishiro%AKikugawa, Naoki%AUji, Shinya%AGraf, David%AMorinari, Takao%AWang, Teng%AMu, Gang%BJournal Name: npj Quantum Materials; Journal Volume: 7; Journal Issue: 1; Related Information: CHORUS Timestamp: 2022-11-24 14:00:59 %D2022%INature Publishing Group; None %JJournal Name: npj Quantum Materials; Journal Volume: 7; Journal Issue: 1; Related Information: CHORUS Timestamp: 2022-11-24 14:00:59 %K %MOSTI ID: 10381687 %PMedium: X %TAnomalous high-field magnetotransport in CaFeAsF due to the quantum Hall effect %XAbstract

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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