Figure 3 : Modulation of the 0.7 anomaly.

From: Wigner and Kondo physics in quantum point contacts revealed by scanning gate microscopy

Figure 3

The figure analyses the zero-bias conductance oscillations when the tip is scanned along the orange line 3 indicated in a with the origin of positions in the QPC direction. (b) Trans-conductance dG/dVgate versus tip position and gate voltage. Black regions correspond to transitions between plateaus. The conductance oscillations are only visible below the first plateau. (c) Conductance G versus tip position for gate voltages Vgate=−0.964, −0.983, −0.992, −1.000, −1.006 and −1.012 V (from top to bottom). Conductance extrema at Vgate=−1 V (green curve) are labelled A to D (maxima) and A’ to D’ (minima). The global slope corresponds to the rise of the saddle-point potential when the tip approaches the QPC. (d) Conductance G versus gate voltage for different tip positions from 0 to 450 nm (successive curves are shifted to the left). (e) Same data as in d but for tip positions A to D (red curves, shifted vertically) and A′ to D′ (blue curves, shifted also horizontally to be compared with red curves). Red curves show no shoulder, whereas blue curves show the 0.7 anomaly. Small differences between plateau values come from residual interference fringes.