Graphite is a model system for the study of three-dimensional electrons and holes in the magnetic quantum limit, in which the charges are confined to the lowest Landau levels. We report magneto-transport measurements in pulsed magnetic fields up to 60 T, which resolve the collapse of two density wave states in two, electron and hole, Landau levels at 52.3 and 54.2 T respectively. We report evidence for a commensurate density wave at 47.1 T in the electron Landau level. The theoretical modelling of these results predicts that the ultra-quantum limit is entered above 73.5 T. This state is an insulator, and we discuss its correspondence to the "metallic" state reported earlier. We propose that this (interaction-induced) insulating phase supports surface states that carry no charge or spin within the planes, but does however support charge transport out of plane.
@article{arxiv.1411.3323,
title = {Charge density waves in graphite; towards the magnetic ultra-quantum limit},
author = {F. Arnold and A. Isidori and E. Kampert and B. Yager and M. Eschrig and J. Saunders},
journal= {arXiv preprint arXiv:1411.3323},
year = {2017}
}