Phase diagram of the semimetal graphite in the magnetic ultra-quantum limit

Strong correlations within the lowest Landau levels of semimetals in their ultra-quantum limit give rise to collective phenomena and topologically non-trivial states. Using state-of-the-art pulsed magnetic fields up to 60 T applied to a high-quality single crystal of graphite, we find a series of field-induced transitions into collinear charge-density wave states. Our analysis establishes the phase diagram of graphite in its ultra-quantum limit. The results imply the existence of a novel topologically-protected chiral edge state at high fields, supporting both charge and spin currents.