The electronic structure of a graphene quantum dot: Electric-field-induced evolution in two subspaces

Abstract

The tight-binding method is employed to investigate the effects of three typical in-plane electric fields on the electronic structure of a triangular zigzag graphene quantum dot. The calculation shows that the single-electron eigenstates evolute independently in two subspaces no matter how the electric fields change. The electric field with fixed-geometry gates chooses several scattered parts of the zero-energy eigenspace as the new zero-energy eigenstates, regardless of the field strength. Moreover, the new zero-energy eigenstates remain unchanged and the associated levels are linear as the field strength. In contrast, the new nonzero-energy eigenstates mix mutually and the associated levels are nonlinear as the field strength. By comparing the effects of three electric fields, we demonstrate that the degeneracy of the zero-energy eigenstates accounts for the linearity of the associated levels.

References in corpus (5)

• Electric Field Effect in Atomically Thin Carbon Films
• Substrate-induced band gap opening in epitaxial graphene
• Metallic Graphene Nanodisks
• Energy levels of triangular and hexagonal graphene quantum dots: a comparative study between the tight-binding and the Dirac approach
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Cited by in corpus (3)

• Graphene nanoflakes in external electric and magnetic in-plane fields
• The optical selection rules of a graphene quantum dot in external electric fields
• Electrically-induced polarization selection rules of a graphene quantum dot