Antiferromagnetic Ordering in Bowtie and AA-Stacking Bilayer Trapezoidal Graphene Nanoflakes: A Comparison Study

Herein, a comparative computational study inquiring about ground state magnetic properties of a nanometer-size bowtie graphene quantum dot with an AA-stacking bilayer trapezoid counterpart based on the single-orbital Hubbard model and density functional theory (DFT) is presented. The structures have an antiferromagnetic ground state with a 1-to-1 correspondence between the local spin polarizations of the two systems. The tight-binding energy spectra look different. However, a similar fashion in the energy spectra emerges after considering the Hubbard interaction term. A comparison between the spatial distributions of edge states shows that the wave functions in both structures are sublattice polarized by proposing a specific unit cell in the bilayer case. In addition, the on-site coulombic repulsion consequence on the rising of magnetization and the size of the local magnetic moment has been considered.

Automated summary

In this study, a comparative computational analysis was conducted to investigate the ground state magnetic properties of a nanometer-sized bowtie graphene quantum dot and its AA-stacking bilayer trapezoid counterpart. The analysis was based on the single-orbital Hubbard model and density functional theory (DFT). The results showed that both structures exhibit an antiferromagnetic ground state with a corresponding local spin polarization. The tight-binding energy spectra appear different, but a similar pattern emerges after considering the Hubbard interaction term. The spatial distribution of edge states suggests that the wave functions in both structures are sublattice polarized, particularly in the bilayer case where a specific unit cell was proposed. Furthermore, the impact of on-site Coulombic repulsion on magnetization and the size of the local magnetic moment was also considered.