Paper detail

Wave function description of conductance mapping for quantum Hall electron interferometer

Scanning gate microscopy of quantum point contacts (QPC) in the integer quantum Hall regime is considered in terms of the scattering wave functions with a finite-difference implementation of the quantum transmitting boundary approach. Conductance ($G$) maps for a clean QPC as well as for a system including an antidot within the constriction are evaluated. The step-like locally flat $G$ maps for clean QPCs turn into circular resonances that are reentrant in external magnetic field when the antidot is introduced to the constriction. The current circulation around the antidot and the spacing of the resonances at the magnetic field scale react to the probe approaching the QPC. The calculated $G$ maps with a rigid but soft antidot potential reproduce the features detected recently in the electron interferometer [F. Martins et al. Nature Sci. Rep. 3, 1416 (2013)].