Carbon nanotube with pressure inducing pseudogaps: Kondo effect study

TL;DR

This study investigates how hydrostatic pressure induces pseudogaps in carbon nanotubes and affects the Kondo effect, revealing pressure-driven changes in electronic properties and conductance.

Contribution

It models pressure effects via out-of-plane distortion and demonstrates the pressure-induced suppression of the Kondo peak in a T-shaped SWNT system.

Findings

Pressure opens a gap in the density of states.

Kondo peak diminishes as the gap forms.

Conductance is strongly influenced by pressure.

Abstract

In this work we are interested to studying the Kondo effect present in a system with a $T$-shape ligation between a single-wall carbon nanotube (SWNT) and a magnetic impurity. The system has been studied under hydrostatic pressure and it was observed the opening of the gap in the density of states of the zigzag metallic tube. The pressure can be modeled by the Pierls instability and in this work we consider the out-of-plane distortion. A tight-binding approximation is used to calculate the SWNT Green's functions with hydrostatic pressure applied. We studied the disappearance of the Kondo peak as the gap opens. Moreover, we observed the strong influence of the pressure in the conductance curve that can be explained by the variation of Kondo peak height. The Kondo effect was reproduced with the atomic approach with $U\rightarrow\infty$ developed previously. Results of the electronic density of states and curves of the conductance are presented.