Bulletin of the American Physical Society
APS March Meeting 2010
Volume 55, Number 2
Monday–Friday, March 15–19, 2010; Portland, Oregon
Session K1: Poster Session II (2:00 pm - 5:00 pm)
Tuesday, March 16, 2010
Room: Exhibit CD
Abstract ID: BAPS.2010.MAR.K1.193
Abstract: K1.00193 : Effects of electric fields on energy gap in bilayer graphene nanoribbons*
Preview Abstract Abstract
Electronic properties of bilayer graphene nanoribbons are investigated by using the tight-binding model with transverse electric fields. They are mainly determined by the external fields, the ribbon edges, and the ribbon width ($N_y$). All bilayer zigzag ribbons are semiconductors, while bilayer armchair ribbons are semiconductors for $N_y \ne 3I+2$ ($I$ an integer). The electric fields modifies the energy dispersions, alters the subband spacing, switches the band gap ($E_g$), and causes the semiconductor-metal (or metal- semiconductor) transitions. In bilayer zigzag ribbons, electric fields not only lifts the degeneracy of partial flat bands at $E_F$ but also switches off $E_g$. $E_g$ is dependent on the ribbon width, ribbon edges, and the field strength. The semiconductor-metal transitions occur in both armchair ribbons and zigzag ribbons in the increase in electric fields. Due to electric fields, the above-mentioned effects are completely reflected in the features of density of states, such as the generation of special structures, the shift of peak position, and the alternation of band gap. The predicted electronic properties could be verified by scanning tunneling microscope conductance and optical absorption measurements.
*This project is financially sponsored by NSC (97-2112-M-244-001-MY2).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.K1.193
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