Fig. 4: Carrier density analysis.
a Conventional Hall coefficient, RH, vs QL number. Filled black circles and empty magenta diamonds represent experimentally measured RH of 1–10 QL FGT films at 5 K and calculated sheet Hall coefficient, respectively. Both results demonstrate a decreasing trend of RH with increasing thickness. The gray dashed line denotes the fitting of experimental RH of 2–10 QL films to RH(N) = λ/N (λ: fitting parameter, N: the number of QL). b 2D carrier density normalized by QL number, extracted from the conventional Hall response. c 2D carrier density at temperatures near, but below TC, determined by vanishing remnant resistance. The light green horizontal line is a guide to the eye. The values of the 2D carrier density are roughly constant at TC. Unfilled circles correspond to measurements taken on different samples that had the same thicknesses. d The calculated ID(EF) (solid line, filled markers) and magnetization m per Fe atom (dashed line, empty markers) as a function of thickness. The ∞ QL indicates bulk. The triangles (blue-colored), squares (red), and circles (green) show the Fe I, Fe II and their average values, respectively. The thick gray line for Fe II is a guide to the eye.
