Strain induced edge magnetism at zigzag edge of a graphene quantum dot

We study the temperature dependent magnetic susceptibility of a strained graphene quantum dot by using the determinant quantum Monte Carlo method. Within the Hubbard model on a honeycomb lattice, our unbiased numerical results show that a relative small interaction $U$ may lead to a edge ferromagnetic like behavior in the strained graphene quantum dot, and a possible room temperature transition is suggested. Around half filling, the ferromagnetic fluctuations at the zigzag edge is strengthened both markedly by the on-site Coulomb interaction and the strain, especially in low temperature region. The resultant strongly enhanced ferromagnetic like behavior may be important for the development of many applications.T.M. thanks CAEP for partial financial support. This work is supported by NSFCs (Grants No. 11374034 and No. 11334012), the Fundamental Research Funds for the Central Universities, and is partially supported by the FEDER COMPETE Program and by the Portuguese Foundation for Science and Technology (FCT) through Grant PEstC/FIS/UI0607/2013. We acknowledge support from the EC under Graphene Flagship (Contract No. CNECT-ICT-604391)