Spin transitions driven by electric dipole spin resonance in fluorinated single- and bilayer-graphene quantum dots

TL;DR

This study explores how electric dipole spin resonance can induce spin transitions in fluorinated graphene quantum dots, revealing mechanisms for fast spin flips and the effects of fluorination and surface deformation.

Contribution

It demonstrates that fluorination and surface deformation enable electric field-driven spin flips with shorter timescales than typical relaxation, advancing quantum control in graphene-based systems.

Findings

Fluorination lifts valley degeneracy and reduces orbital magnetic moments.

Spin-orbit coupling from surface deformation enables electric-field-driven spin flips.

Spin flip times are shorter than experimental spin relaxation times.

Abstract

Spin transitions driven by a periodically varying electric potential in dilute fluorinated graphene quantum dots are investigated. Flakes of monolayer graphene are considered as well as electrostatic electron traps induced in bilayer graphene. The stationary states are obtained within the tight-binding approach and are used to the basis of eigenstates to describe the system dynamics. The dilute fluorination of the top layer lifts the valley degeneracy of the confined states and attenuates the orbital magnetic dipole moments due to current circulation within the flake. Moreover, the spin-orbit coupling introduced by the surface deformation of the top layer induced by the adatoms allows spin flips to be driven by the AC electric field. For the bilayer quantum dots the spin flip times is substantially shorter than the experimental spin relaxation. Dynamical effects including many-photon and multilevel transitions are also discussed.