Extended Data Fig. 6: Disorder and the quantum Hall effect.
From: Dynamic band-structure tuning of graphene moiré superlattices with pressure
a, Device disorder δn is measured as the n necessary to dope between the maximum and minimum Rxy, averaged over B = 0.25 T to 0.75 T. b, Density fluctuations as a function of pressure across different devices. The error bars denote the uncertainty in picking the peak positions of Rxy. c, ρxx (solid lines, left axis) and σxy (dotted lines, right axis) of device P1 at B = 12.5 T. Symmetry-broken integer quantum Hall states become much more clearly developed with pressure, and fractional quantum Hall states begin to emerge as well. Both are offset for clarity. d, ρxx of device P2 at B = 9 T, similarly showing an improvement in the quantum Hall response. Surprisingly, the improvement persists even after the pressure is released back to vacuum and the device is cleaned in solvents (green curve). Curves are vertically offset for clarity.
