Electric-field controlled spin in bilayer triangular graphene quantum dots

TL;DR

This paper demonstrates theoretically that an external electric field can control the magnetic properties of bilayer triangular graphene quantum dots, enabling the switching of spin states and potential qubit applications.

Contribution

It introduces a method to manipulate spin states in bilayer graphene quantum dots using electric fields, combining mean-field and many-body approaches.

Findings

Electric field can switch the total spin of the quantum dot.

Magnetic interaction changes from ferromagnetic to non-magnetic at a critical field.

Potential for qubit isolation from contacts and nuclear spins.

Abstract

We present theoretical results based on mean-field and exact many-body approaches showing that in bilayer triangular graphene quantum dots with zigzag edges the magnetism can be controlled by an external vertical electric-field. We demonstrate that without electric field the spins of the two layers of the quantum dot interact ferromagnetically. At a critical value of the electric-field, the total spin of the bilayer structure can be turned off or reduced to a single localized spin, a qubit isolated from contacts and free from interaction with nuclear spins.