Extended Data Fig. 4: Thomas-Fermi simulations of the QPC pinch-off.
(a) The filling at the center of the QPC, νQPC as a function of VB and VNS + αVB, with the bulk filling of the east/west regions fixed at νEW = − 6. The result qualitatively mimics the measured GD shown in Fig. 4a since νQPC determines the number of transmitted modes and therefore the diagonal conductance. Two line cuts which correspond to EV/EC = 2.2 and 4.4 are shown in Fig. 4c. (b-c) Calculated filling factor ν for a realistic device geometry at B = 2 T for (b) EV/EC = 4.4 and (c) EV/EC = 2.2. When EV/EC = 2.2, there exists an incompressible island with νQPC = − 4 at the center of the QPC. Contours of ν = n + 1/2 are shown as white dotted lines, indicating the location of chiral edge modes, two-pairs of which are transmitted through the QPC. This illustrates the rule NQPC = νQPC + 2.
