  Here, the magnetic susceptibility of a triangular-graphene-quantum-dot-like
system was examined by using the determinant quantum Monte Carlo method. We
focused on three zigzag edge quantum dots or rings, namely, the triangular
graphene quantum ring, bilayer triangular graphene quantum dot, and bilayer
triangular graphene quantum ring. The triangular-graphene-quantum-dot-like
system exhibited robust edge ferromagnetic behavior, which was independent of
size, monolayer or bilayer, or dot or ring shape, according to the numerical
results. At half filling, the edge magnetic susceptibility is increased by
on-site interactions, especially in the low-temperature region. Spintronics
systems may benefit from use of this system due to its robust edge
ferromagnetic behavior.
