Fig. 1: Fractional-integer quantum Hall junction.
From: Andreev reflection of fractional quantum Hall quasiparticles
a, b False-colour scanning electron micrograph of the Hall-bar sample with measurement configurations (a) and magnified view near the narrow junction (b). A perpendicular magnetic field B = 9 T is applied from the back to the front of the sample. The v = 1 states develop over the wide blue regions in the 2DES with the front-gate voltages, including VR, set at 0 V. Meanwhile, electron density below one of the front gates (red region) is reduced to form the v = 1/3 state by applying VL = −0.42 V. A narrow 1/3-1 junction is formed by depleting the 2DES under the split gate electrodes (yellow) with negative VS. Chiral edge states are displayed by arrows (blue, between v = 1 and v = 0; red, between v = 1/3 and v = 0). Vin is the applied source-drain voltage, I is the measured current, and Vi (i = 1–4) are the measured voltages of the incoming and outgoing channels of the 1/3-1 junction. c Schematic of the experimental setup. A narrow junction is formed between v = 1/3 and v = 1 states.
