A Γ=|t|/100 broadening and an overlap s=0.13 are assumed. In Figure 2, we show a pictorial view of the different studied systems in (a) a nanodisk center, (b) a one-pentagon nanocone apex, and (c) a two-pentagon nanocone apex. Atoms with different colors (numbers) indicate different point symmetries for each system. Figure 2 Some relevant atomic sites. Pictorial view of (a) a nanodisk center, (b) a one-pentagon nanocone apex, and (c) a two-pentagon nanocone apex. Atoms with different colors/numbers indicate different point symmetries for each system. Different plots in Figure 3 show the

density of states averaged over the N C atoms and the LDOS for a CND (Figure 3a,d), a single-pentagon CNC (Figure 3b,e), and for a two-pentagon CNC (Figure 3c,f), Selleck CAL-101 for N C =258,245, and 246, respectively. All results are shown in an energy range around ε 2p=0. Figure 3 Density of states for small systems. (Color Online) DOS

and LDOS for a N C = 258 nanodisk (a,d), I-BET-762 ic50 a N C = 245 one-pentagon nanocone (b,e), and a N C = 246 two-pentagon nanocone (c,f). LDOS curves for the different atoms shown in Figure 2, solid line (black atom 1), dashed line (red atom 2), and dotted line (blue atom 3). AMN-107 cell line Vertical lines in each panel indicate the position of the Fermi energy. As expected, for small finite systems, the DOS, LDOS, and the position of the Fermi energy depend on the number of atoms considered in the numerical calculation and on their characteristic

geometries [21–23] and topology [24, 25]. The experimental results by Ritter and Lyding [5] give actually a true conclusion about the influence of edge structure on the electronic structures of graphene quantum dots and nanoribbons. A remarkable difference between CND and CNCs structures is the existence of a finite DOS above the Fermi level for nanocones. This clear metallic character of the DOS for nanocones is more robust for the two-pentagon CNC [22, 26]. This feature is a consequence of a symmetry break induced by the presence of topological defects in the CNC lattices, which generates new states above the Fermi energy not present in the CND structure. The contributions to the DOS coming from the apex atoms states are apparent in 4-Aminobutyrate aminotransferase the LDOS of Figure 3e,f. Also notice that for the two-pentagon case, in which there is a large topological disorder, the LDOS spectra exhibit significant differences depending on the point symmetry of the considered atom (cf. Figure 2). For increasing number of atoms, the total DOS for the different nanostructures is very similar to the corresponding DOS of a graphene layer, except for the edges states which show up as a peak at the Fermi energy, as shown in Figure 4a,b,c. It is interesting to note that the apex atomic states do not contribute to the total DOS near the Fermi energy but mainly near the graphene-like van Hove peaks.