Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 26: Poster Session

MM 26.30: Poster

Dienstag, 23. März 2010, 14:45–16:30, Poster C

Electronic Properties of Graphene Nanoribbons — •Ezgi Erdogan and Gotthard Seifert — Theoretische Chemie, TU Dresden, 01062 Dresden

The aim of present work is to review the electronic properties of Graphene nanoribbons (GNR) with the density functional tight binding method (DFTB) based on molecular dynamics (MD) simulation in the NVT ensemble for investigating energy gaps, defect area, strain effect and to understand switching between metallic and semiconducting properties. MD simulations are performed on Armchair GNR (AGNR) with (12,7,196) and (17,7,266) indexes and Zigzag GNR (ZGNR) with (20,9,198) and (22,9,216) indexes. The indexes (a,b,c) refer to ’a’ - the width in number of carbon atoms, ’b’ - the unit cell and ’c’ - the total number of atoms in the configuration of the graphene sheet. The Graphene edges are saturated by hydrogen atoms. AGNRs are always semiconducting. The AGNR(12) has a 0.7 eV gap. During stretching process, one or two C-atom chains remain between two graphene halves. DOS pretends a switch to metallicity at a strain of 16%, but for the chain of single carbon atoms a band gap is visible in local density of states (LDOS). For AGNRs no change from semiconducting to metallic behavior for any value of strain is observed in transport calculations with a Green’s function method. In contrast, ZGNRs remain conducting.