Fully Tunable Fano Resonances in Chiral Electronic Transport

TL;DR

This paper introduces a tunable Fano resonance in chiral electronic transport using a Mach-Zehnder-Fano interferometer, enabling full control over resonance profiles and spectra without direct path interference.

Contribution

It proposes a novel electronic interferometer design that achieves fully controllable Fano resonances in chiral transport, challenging traditional interference assumptions.

Findings

Perfect Fano profiles are achieved and fully tunable via magnetic flux.

Transport spectra exhibit a consistent evolution pattern resistant to parameter changes.

Backscattering suppression enables precise control of resonance characteristics.

Abstract

Fano resonance is believed to arise when a direct path interferes with a resonant path. We demonstrate that this is not true for chiral electronic transmission without additional direct paths. To address the Fano effect in chiral electronic transport, we suggest an electronic Mach-Zehnder-Fano interferometer (MZFI), which combines a quantum dot with an electronic Mach-Zehnder interferometer. Backscattering is completely suppressed in chiral electronic transport, yielding perfect Fano profiles that can be fully adjusted by an external magnetic flux in the transmission, linear conductance, and differential spectra. Even the current and shot noise for a symmetric interferometer with two arms of the same length exhibit fully controllable resonances and distinct Fano resonance characteristics. Along with the profiles, all of the transport spectra follow the same evolution pattern in a cycle that is resistant to changes in the device's defining parameters.