Taming the magnetoresistance anomaly in graphite

Abstract

At low temperatures, graphite presents a magnetoresistance anomaly which manifests as a transition to a high-resistance state (HRS) above a certain critical magnetic field Bc. Such HRS is currently attributed to a c-axis charge-density-wave taking place only when the lowest Landau level is populated. By controlling the charge carrier concentration of a gated sample through its charge neutrality level (CNL), we were able to experimentally modulate the HRS in graphite for the first time. We demonstrate that the HRS is triggered both when electrons and holes are the majority carriers but is attenuated near the CNL. Taking screening into account, our results indicate that the HRS possess a strong in-plane component and can occur below the quantum limit, being at odds with the current understanding of the phenomenon. We also report the effect of sample thickness on the HRS.