Charge localization and dynamical spin locking in double quantum dots driven by ac magnetic fields

TL;DR

This paper explores how ac magnetic fields can control electron localization and spin states in double quantum dots, enabling charge confinement and spin freezing through parameter tuning.

Contribution

It demonstrates the ability of ac magnetic fields to induce charge localization and spin locking, revealing the role of Hamiltonian symmetry in quasienergy degeneracies.

Findings

Charge localization achieved via tuning ac magnetic field parameters.

Spin locking occurs at specific field conditions, unlike with ac electric fields.

Quasienergy degeneracies relate to Hamiltonian symmetry and affect dynamics.

Abstract

We investigate electron localization and dynamical spin locking induced by ac magnetic fields in double quantum dots. We demonstrate that by tuning the ac magnetic fields parameters, i.e., the field intensity, frequency, and the phase difference between the fields within each dot, coherent destruction of tunneling (and thus charge localization) can be achieved. We show that in contrast with ac electric fields, ac magnetic fields are able to induce spin locking, i.e., to freeze the electronic spin, at certain field parameters. We show how the symmetry of the Hamiltonian determines the quasienergy spectrum which presents degeneracies at certain field parameters, and how it is reflected in the charge and spin dynamics.