Electron transport in interacting hybrid mesoscopic systems

TL;DR

This paper presents a unified theoretical framework for analyzing electron transport in hybrid mesoscopic systems with interactions, accommodating ferromagnetic and superconducting leads, and ensuring gauge invariance and measurable quantities.

Contribution

It introduces a comprehensive theory that generalizes existing formulas, like Meir-Wingreen, for complex hybrid systems with interactions and different lead types.

Findings

Provides gauge-invariant current formulas for hybrid systems.

Clarifies measurable quantities in transport experiments.

Unifies treatment of ferromagnetic and superconducting leads.

Abstract

A unified theory for the current through a nanoscale region of interacting electrons connected to two leads which can be either ferromagnet or superconductor is presented, yielding Meir-Wingreen-type formulas when applied to specific circumstances. In such a formulation, the requirement of gauge invariance for the current is satisfied automatically. Moreover, one can judge unambiguously what quantities can be measured in the transport experiment.