Impurity effects on the resonant Andreev reflection in a finite-sized carbon nanotube system

TL;DR

This paper theoretically investigates how impurities affect resonant Andreev reflection in finite-sized carbon nanotubes, revealing that impurity strength and nanotube length significantly influence the reflection process.

Contribution

It provides a detailed analysis of impurity effects on Andreev reflection in carbon nanotubes, highlighting the role of electron-hole symmetry breaking.

Findings

Impurities reduce resonant Andreev reflection when breaking electron-hole symmetry.

Reflection depends on impurity strength and nanotube length.

Impurity effects vary with bias voltage.

Abstract

The influence of the impurity on the resonant Andreev reflection through a normal-metal/carbon-nanotube/superconductor system is studied theoretically. It is found that the resonant Andreev reflection depends on the strength of the impurity and the length of the armchair nanotube. The impurity which breaks the electron-hole symmetry of the nanotubes greatly reduces the resonant Andreev reflection. The symmetry broken depends distinctly on the impurity strength. The impurity effects on the Andreev reflection current at different bias are also studied.