The Edge Magnetization and Strip Phase of Graphene Quantum Dots with Long-Range Coulomb Interaction
We investigate the magnetism and optical absorption properties of charge neutral hexagonal graphene quantum dots (GODs) terminated with zigzag edges by using a tight-binding Hubbard type model for the 7r electrons. Within the Hartree Fock approximation and taking into account the long-range Coulomb...
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Veröffentlicht in: | Chinese physics letters 2014-04, Vol.31 (4), p.150-154 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We investigate the magnetism and optical absorption properties of charge neutral hexagonal graphene quantum dots (GODs) terminated with zigzag edges by using a tight-binding Hubbard type model for the 7r electrons. Within the Hartree Fock approximation and taking into account the long-range Coulomb interaction, our cal- culation yields a ferromagnetic ground state with magnetic moments localized on the edges for GODs, and also gives an antiferromagnetism state with the energy very c/ose to the ferromagnetism ground state. We find that both the ferromagnetic and the antiferrornagnetic states have stripe patterned charge density distributions as a result of the long-range Coulomb interaction. The optical conductivity for GQDs has an energy gap in the low frequency regime in contrast to the bulk neutral graphene sheet where a universal constant is approached. |
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ISSN: | 0256-307X 1741-3540 |
DOI: | 10.1088/0256-307X/31/4/047303 |