Emergence of novel magneto-oscillations near the charge neutrality point in dc current biased graphene

Understanding of many-particle interaction effects on the zeroth Landau level (zLL) in graphene is of great interest and importance in modern condensed matter physics. Typical magnetotransport experiments in this regime are performed at small ac currents, with perpendicular magnetic fields.  In this work, we explore magnetotransport in the non-equilibrium regime by introducing high dc currents in addition to small ac excitations in a large area, high mobility graphene-hBN heterostructure.  The high dc current density (1 A/m) introduces a Hall field, resulting in the tilting of LLs. Shubnikov-de Haas oscillations corresponding to higher LL indices (ν = 18, 14, 10, 6) were found to be shifted with dc current. Intriguingly, we observe novel magnetoresistance oscillations near the zLL that develop as a function of dc current.  These oscillations show a non-linear dispersive behavior as a function of carrier density and magnetic field.  Overall, our experimental findings show signatures of inter-LL transitions in the higher LLs and Hall field-induced insulating states near the charge neutrality point.