Bias driven circular current in a ring nanojunction: Critical role of environmental interaction

TL;DR

This paper investigates how environmental interactions influence bias-driven circular currents in ring nanojunctions, revealing that disorder can both enhance and suppress current, with implications for experimental detection and device design.

Contribution

It introduces a theoretical framework showing the critical impact of backbone disorder and environmental interactions on circular currents in nanojunctions, supported by broad parameter analysis.

Findings

Circular current is zero in symmetric junctions without disorder.

Disorder can induce and then suppress circular current at high levels.

Results are applicable across a wide range of physical parameters.

Abstract

The specific role of environmental interaction on bias driven circular current in a ring nanojunction is explored within a tight-binding framework based on wave-guide theory. The environmental interaction is implemented through disorder in backbone sites where these sites are directly coupled to parent lattice sites of the ring via single bonds. In absence of backbone disorder circular current becomes zero for a lengthwise symmetric nanojunction, while it increases with disorder which is quite unusual, and after reaching a maximum it eventually drops to zero in the limit of high disorder. The effects of ring-electrode interface configuration, ring-backbone coupling, different types of backbone disorder and system temperature are critically investigated. All the studied results are valid for a broad range of physical parameters, giving us confidence that the outcomes of this theoretical work can be verified experimentally. To make this study self-contained, we also discuss the feasibility of detecting bias-driven circular current and provide design guidelines for implementing our proposed quantum system in a laboratory.