Fig. 1: Device design.

a Schematic of our GaAs/AlGaAs heterostructure consisting of a primary GaAs quantum well flanked by ancillary GaAs screening wells. b False color atomic force microscopy image of the interferometer studied in this work. Yellow regions are the metallic gates that define the interference path with a lithographic area 0.58 μm². c Bulk R_xy and diagonal resistance R_D across the interferometer, demonstrating overlapping plateaux at integer quantum Hall states. The QPCs are biased at V_QPC = −0.9 V, and the plunger gate is biased at V_PG = −0.7 V, just past depletion. The top gate in the center of the interferometer is grounded during all measurements.