Fig. 2: Signatures of Andreev reflection.
From: Andreev reflection of fractional quantum Hall quasiparticles
a Two-terminal conductance G as a function of split-gate voltage VS, taken with VL = −0.42 V. Below VS ≅−0.55 V (indicated by a dashed line), the 2DESs underneath the split gate electrodes are depleted to form a narrow 1/3-1 junction. Conductance oscillations with G > e2/3h, the evidence of the Andreev reflection, are observed. (Inset) G as a function of leftmost top gate voltage VL measured with VS = 0, indicating that a v = 1/3 state forms at VL = −0.42 V in the region immediately to the left of the junction (red region in Fig. 1a, b). b, c VS dependence of the voltages on the incoming (V1 and V3) and outgoing (V2 and V4) channels, measured in the same setup as in (a) on the v = 1/3 (b) and v = 1 (c) sides of the junction. The vertical axes are normalised by the source-drain voltage Vin. Both negative output (V2 < 0) in the reflected channel and overshoot (V4 > Vin/3) in the transmitted channel are the signatures of the Andreev reflection.
