Aharonov-Casher effect and quantum transport in graphene based nano rings: A self-consistent Born approximation

TL;DR

This paper theoretically investigates the Aharonov-Casher effect in graphene nano rings with Rashba spin-orbit coupling, analyzing quantum transport and oscillations influenced by relaxation and dephasing mechanisms.

Contribution

It introduces a self-consistent Green's function approach to study the Aharonov-Casher effect in graphene nano rings considering relaxation effects.

Findings

Measurable Aharonov-Casher oscillations in current due to Rashba coupling.

Oscillation amplitude suppressed by impurity-induced relaxation.

Oscillations persist in dilute impurity regimes.

Abstract

In this study, Rashba coupling induced Aharonov-Casher effect in a graphene based nano ring is investigated theoretically. The graphene based nano ring is considered as a central device connected to semi-infinite graphene nano ribbons. In the presence of the Rashba spin-orbit interaction, two armchair shaped edge nano ribbons are considered as semi-infinite leads. The non-equilibrium Green's function approach is utilized to obtain the quantum transport characteristics of the system. The relaxation and dephasing mechanisms within the self-consistent Born approximation is scrutinized. The Lopez-Sancho method is also applied to obtain the self-energy of the leads. We unveil that the non-equilibrium current of the system possesses measurable Aharonov-Casher oscillations with respect to the Rashba coupling strength. In addition, we have observed the same oscillations in dilute impurity regimes in which amplitude of the oscillations is shown to be suppressed as a result of the relaxations.