Controlling the Band Gap in Zigzag Graphene Nanoribbons With an Electric Field Induced by a Polar Molecule
Sergio Dalosto, Zachary H. Levine
Graphene nanoribbons with both armchair- and zigzag-shaped hydrogen-passivated edges (AGNR and ZGNR) have band gaps. Son et al. showed that the gap s value depends on the width of the ribbon and that the application of a uniform external electric field Eext across a ZGNR reduces the band gap. Moreover, for a critical Eext, the ZGNR becomes half-metallic. In the case of an 8-chain zigzag ribbon, the critical Eext is 2 V/nm within the local-density approximation (LDA). Motivated by tese findings, we study the influence on the gap of the electric field produced by a polar ad-molecule to the surface on an 8-zigzag ribbon. The formula units of the ad-molecules studies are NH3(CH)6CO2 and NH3(CH)10CO2. We show that the band gap is reduced from 0.52 eV without the ad-molecule to 0.28 eV with the ad-molecule within the generalized gradient approximation (GGA). Also, combining Eext of 1 V/nm and the ad-molecule induces the 8-chain ribbon to become half-metallic. These results suggest possible uses for the grapheme nanoribbons as sensors or switching devices.
and Levine, Z.
Controlling the Band Gap in Zigzag Graphene Nanoribbons With an Electric Field Induced by a Polar Molecule, Nano Letters
(Accessed December 8, 2023)