Magneto-transport in a quantum network: Evidence of a mesoscopic switch

TL;DR

This paper studies magneto-transport in a mesoscopic quantum network, demonstrating a switch between high and low conductance states due to localized states induced by a middle arm, with potential applications in quantum devices.

Contribution

It introduces a model showing how a middle arm in a quantum ring induces localized states that enable conductance switching, expanding understanding of quantum network control.

Findings

Localized states cause conductance switching behavior.

Persistent current analysis supports the switching mechanism.

The model can be applied to complex quantum networks.

Abstract

We investigate magneto-transport properties of a $\theta$ shaped three-arm mesoscopic ring where the upper and lower sub-rings are threaded by Aharonov-Bohm fluxes $\phi_1$ and $\phi_2$, respectively, within a non-interacting electron picture. A discrete lattice model is used to describe the quantum network in which two outer arms are subjected to binary alloy lattices while the middle arm contains identical atomic sites. It is observed that the presence of the middle arm provides localized states within the band of extended regions and lead to the possibility of switching action from a high conducting state to a low conducting one and vice versa. This behavior is justified by studying persistent current in the network. Both the total current and individual currents in three separate branches are computed by using second-quantized formalism and our idea can be utilized to study magnetic response in any complicated quantum network. The nature of localized eigenstates are also investigated from probability amplitudes at different sites of the quantum device.