 Fourfold graphene Hall sequence

With unresolved spin and valley splittings, each graphene Landau level has areal degeneracy $4e|B|/h$. Counting carriers from a half-filled zero level yields integer Hall plateaux at filling factors $\pm 2,\pm 6,\pm 10,\dots$. For fixed positive density $n$, plateau-centre fields are $nh/(e\nu )$ and ideal extended-level centres have $B_j=nh/(4ej)$. Localization and level broadening determine finite plateau widths; degeneracy counting does not determine them.