Fig. 3: Electrical transport measurements.
a Mean mobility μ as a function of density n at T = 1.7 K obtained by averaging measurements from 10 H-FETs fabricated on the heterostructure with a 6.9(5) nm quantum well. The shaded region represents one, two, and three standard deviations of μ at a fixed n. Data from this heterostructure are colour-coded in purple in all subsequent figures. b Mean conductivity σxx as a function of n and fit to the percolation theory52 in the low-density regime (solid line). c, d Distributions of mobility μ measured at n = 6 × 1011 cm−2 and percolation density np for heterostructures featuring quantum wells of different thickness w: 9.0(5) nm (blue, 16 H-FETs measured and reported in ref. 18), 6.9(5) nm (purple, from the analysis of the same dataset in (a, b)), and 5.3(5) nm (green, 22 H-FETs measured and reported in ref. 18). Violin plots, quartile box plots, and mode (horizontal line) are shown.
