Current vortices in hexagonal graphene quantum dots

TL;DR

This paper investigates how boundary conditions influence electronic current patterns in hexagonal graphene quantum dots, revealing vortex formations that could enable applications in nanomagnetism and sensing.

Contribution

It introduces a combined non-equilibrium Green's function and tight-binding approach to analyze current vortices in graphene quantum dots with various contact placements.

Findings

Current vortices form when contact symmetry conflicts with quantum dot symmetry.

Vortices indicate potential for graphene quantum dots in nanomagnetic and sensing applications.

Boundary conditions critically affect electronic current flow patterns.

Abstract

Newly synthesized nanostructures of graphene appear as a promising breeding ground for new technology. Therefore, it is important to identify the role played by the boundary conditions in their electronic features. In this contribution we use the non-equilibrium Green's function method coupled to tight-binding theory to calculate and compare the current patterns of hexagonal graphene quantum dots, with contacts placed at different edge locations. Our results reveal the formation of current vortices when the symmetry of the contact geometry is in conflict with the symmetries of the quantum dot. The presence of current vortices suggests the use of graphene quantum dots as nanomagnets or magnetic nanosensors.