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Open Access Nano Express

Electronic and transport properties in circular graphene structures with a pentagonal disclination

Esther Jódar1*, Antonio Pérez–Garrido1 and Fernando Rojas12

Author Affiliations

1 Departamento de Física Aplicada, Antiguo Hospital de Marina, Campus Muralla del Mar, UPCT, Cartagena, Murcia 30202, Spain

2 Departamento de Física Teórica, Centro de Nanociencias y Nanotecnologías, UNAM, Apdo. 356, Ensenada, Baja California 22830, Mexico

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Nanoscale Research Letters 2013, 8:258  doi:10.1186/1556-276X-8-258

Published: 29 May 2013

Abstract

We investigate the electronic and transport properties of circular graphene structures (quantum dots) that include a pentagonal defect. In our calculations, we employ a tight-binding model determining total and local density of states, transmission function and participation number. For the closed structure, we observe that the effect of the defect is concentrated mainly on energies near to zero, which is characteristic of edge states in graphene. The density of states and transmission functions for small energies show several peaks associated with the presence of quasi-bound states generated by the defect and localized edge states produced by both the circular boundaries of the finite lattice and induced by the presence of the pentagonal defect. These results have been checked by calculating the participation number, which is obtained from the eigenstates. We observe changes in the available quasi-bound states due to the defect and the creation of new peaks in the transmission function.

Keywords:
Graphene; Transport; Defects; 72.80.Vp; 72.15.Rn; 73.20.At