▎ 摘　　要

The magnetic properties of a hexagonal graphene nanodot are investigated using a configuration-interaction approach. The phase diagram of the nanodot system is obtained for a wide range of Coulomb interaction strengths and dielectric environments, and shows that the magnetic phase transition can be effectively tailored by changing the dielectric environment. Selective magnetic phase between non-magnetic and ferromagnetic could therefore be achieved simply by changing to an appropriate substrate for the graphene nanodot.