Fig. 1: Dissipation regimes in the quantum Hall phase: high-quality graphene at RT.

a Schematics of temperature-dependent transport in conventional quantum Hall systems, such as 2DESs in semiconductors. At low T (relative to the LL separation, upper part), the electrical current is carried by chiral edge states, leading to zero longitudinal resistance. At higher T (lower part), thermally-excited bulk states give a finite resistivity due to disorder scattering (yellow shading), with negligible contribution from lattice vibrations. b At RT, graphene supports both the QH effect (due to large inter-LL spacing) and predominant e-ph scattering in high-mobility samples, enabling the realization of a different transport regime, with phonon-mediated dissipation at high magnetic fields (dark cyan shading). c ρ_xx (black) and σ_xy (red) as a function of the back-gate voltage (corrected by a 5.2 V offset from the CNP), measured in hBN-encapsulated sample D2 at B = 30 T and T = 295 K. Inset: zoom-in of ρ_xx in the vicinity of filling factor ν = 2 (the dark cyan shading indicates the finite value of the resistivity minimum).