Mode-filtered electron injection into a waveguide interferometer

TL;DR

This paper demonstrates the selective injection of mode-filtered electrons into a waveguide interferometer, enabling single-mode transport and phase-sensitive interference in a multi-mode structure.

Contribution

It introduces a tunable quantum point contact for mode-selective electron injection into a waveguide AB ring, enabling coherent single-mode transport.

Findings

Successful mode-filtered electron injection verified by non-local resistance

Observation of phase-sensitive Aharonov-Bohm interference

Demonstration of single-mode transport in a multi-mode waveguide

Abstract

Injection of mode-filtered electrons into a phase-sensitive four-terminal waveguide Aharonov-Bohm (AB) ring is studied. An individually tuneable quantum point contact (QPC) in a waveguide lead of the GaAs/AlGaAs-ring allows to selectively couple to one-dimensional modes in the ring. Thus, we demonstrate single-mode transport in a multi-mode waveguide structure. Coherent mode-filtering by the lowest QPC subband is verified by non-local bend resistance and phase-sensitive AB interference measurements.