(a) Measured logarithmic temperature-dependent conductivity (solid lines) at zero magnetic field for all samples with the edge-to-edge distance between antidots d indicated. The red dashed lines are guide for eyes. (b) Measured logarithmic temperature-dependent conductivity at indicating perpendicular magnetic fields (open circles) for sample d190. Solid lines are the linear fitting curves. (c) Measured temperature-dependent conductivity (solid lines) at B = 2 T for all samples with d indicated. The curves are offset for clarity and the red dashed lines are guide for eyes. (d) The slope obtained by linear fitting the curves in panel (b) is plotted (solid symbols) as a function of the magnetic field for sample d190. Solid lines are guide for eyes. Adapted from Ref. [59].