Andreev-Fano Effect in a Hybrid Normal-Metal / Superconductor Interferometer

TL;DR

This paper introduces the Andreev-Fano effect in a hybrid N/S interferometer with a quantum dot, revealing unique line shapes and phase behaviors due to Andreev reflection, distinct from conventional Fano effects.

Contribution

It reports the discovery of the Andreev-Fano effect, highlighting its unique line shapes and phase dependence in hybrid N/S interferometers, expanding understanding of quantum interference phenomena.

Findings

Line shape is the square of the conventional Fano shape in linear response.

Nonlinear transport shows a sharp resonance on an expanded interference pattern.

Phase dependence differs from all-N or all-S interferometers.

Abstract

We report on a new type of Fano effect, named as Andreev-Fano effect, in a hybrid normal-metal / superconductor (N/S) interferometer embedded with a quantum dot. Compared with the conventional Fano effect, Andreev-Fano effect has some new features related to the characteristics of Andreev reflection. In the linear response regime, the line shape is the square of the conventional Fano shape; while in the nonlinear transport, a sharp resonant structure is superposed on an expanded interference pattern, qualitatively different from the conventional Fano effect. The phase dependence of the hybrid N/S interferometer is also distinguished from those of all-N or all-S interferometers.