Fig. 2: Gate–spectroscopy of outer edge channel interference.

Conductance oscillations were measured by partitioning the outer edge channel with QPC transmission of T₁ = 0.91 and T₂ = 0.94 at V_bg = 1.8 V (ν_B = 2.26). a Gate spectroscopy, FFT amplitude of the oscillation versus V_pg and frequency f at V_DC = − 55.5 μV. FFT is slided over the whole plunger gate voltage range with a 0.2V window. Supplementary Movie 3 shows the dependency of this gate–spectroscopy on the bias voltage. The black and red dashed lines represent the frequency dispersion of the inner f_i (determined from Fig. 1h) and outer f_o edges, respectively. The orange dashed line, calculated as the sum of f_i and f_o, coincides with the strong signal attributed to pairing f_p. Inset schematics show the edge channel configuration, with the red dashed line indicating the partitioned outer channel and the orange wavy line representing inter–channel interaction. b The lobe structures of pairing (orange–colored) and the outer channel (red–colored), extracted from bias–voltage dependent gate–spectroscopy in Supplementary Movie 3. c The pajama map, measured at zero bias V_DC = 0V, shows frequency beating that persists across the entire bias–voltage range (Supplementary Movie 4). Inset: 2D FFT reveals two frequencies–the outer channel f_o and pairing f_p. f_p is shown as the sum of the f_o (red arrow) and f_i (black arrow).