  Vacancies in graphene lead to the appearance of localized electronic states
with non-vanishing spin moments. Using a mean-field Hubbard model and an
effective double-quantum dot description we investigate the influence of strain
on localization and magnetic properties of the vacancy-induced states in
semiconducting armchair nanoribbons. We find that the exchange splitting of a
single vacancy and the singlet-triplet splitting for two vacancies can be
widely tuned by applying uniaxial strain, which is crucial for spintronic
applications.
