CaFeAsF is an iron-based superconductor parent compound whose Fermi surface is quasi-two dimensional, composed of Dirac-electron and Schr\"odinger-hole cylinders elongated along the c axis. We measured the longitudinal and Hall resistivities in CaFeAsF with the electrical current in the ab plane in magnetic fields up to 45 T applied along the c axis 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 is ν = 2 for both electrons and holes at these high field strengths, resulting in a total filling factor ν = νhole−νelectron = 0. We therefore argue that the ν = 0 quantum Hall state emerges under these conditions.
@article{arxiv.2107.10460,
title = {Anomalous High-Field Magnetotransport in CaFeAsF due to the Quantum Hall Effect},
author = {Taichi Terashima and Hishiro T. Hirose and Naoki Kikugawa and Shinya Uji and David Graf and Takao Morinari and Teng Wang and Gang Mu},
journal= {arXiv preprint arXiv:2107.10460},
year = {2022}
}