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Theoretical study of edge states in BC2N nanoribbons with zigzag edges.

Harigaya K, Kaneko T - Nanoscale Res Lett (2013)

Bottom Line: The zigzag BC2N nanoribbons have the flat bands when the atoms are arranged as B-C-N-C along the zigzag lines.In this arrangement, the effect of charge transfer is averaged since B and N atoms are doped in same sublattice sites.This effect is important for not only the formation of flat bands but also for the validity of the tight binding model for such system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Computational Material Science Unit, NIMS, 1-2-1 Sengen, Tsukuba 305-0047, Japan. KANEKO.Tomoaki@nims.go.jp.

ABSTRACT
: In this paper, electronic properties of BC2N nanoribbons with zigzag edges are studied theoretically using a tight binding model and the first-principles calculations based on the density functional theories. The zigzag BC2N nanoribbons have the flat bands when the atoms are arranged as B-C-N-C along the zigzag lines. In this arrangement, the effect of charge transfer is averaged since B and N atoms are doped in same sublattice sites. This effect is important for not only the formation of flat bands but also for the validity of the tight binding model for such system.

No MeSH data available.


The band structures of BC2N nanoribbons of the models A (a), B (b), C (c), and D (d) for N  = 8. In each panel, the result within DFT is shown in (i) and those within TB model are shown in (ii, iii, iv). Note that the center of the energy, E = 0, does not mean the Fermi level in models C and D within TB model. In (c - iv) and (d - iv), the improved band structures by adding the extra site energies at the outermost atoms are indicated by the blue dotted lines.
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Figure 2: The band structures of BC2N nanoribbons of the models A (a), B (b), C (c), and D (d) for N  = 8. In each panel, the result within DFT is shown in (i) and those within TB model are shown in (ii, iii, iv). Note that the center of the energy, E = 0, does not mean the Fermi level in models C and D within TB model. In (c - iv) and (d - iv), the improved band structures by adding the extra site energies at the outermost atoms are indicated by the blue dotted lines.

Mentions: The calculated band structures of BC2N nanoribbons for N = 8 are summarized in Figure2. The band structure of the model A nanoribbon within DFT shown in Figure2a(image i) have nearly degenerate band around the Fermi level. In Figure2a(images ii, iii, and iv), the band structures of the model A nanoribbons within TB model are shown. We observed that the flat bands and the degree of degeneracy depend on EB/t[24]. The band structure for EB/t = 0.7 has the doubly degenerate flat bands at E = 0, but the twofold degeneracy was lifted with increasing EB[24]. The band structure within DFT resembles to that within TB for EB/t = 1.3 shown in Figure2a(image iv). The length of the flat bands increase with increasing of EB, since the shift of the Dirac point of BC2N sheet increases[24].


Theoretical study of edge states in BC2N nanoribbons with zigzag edges.

Harigaya K, Kaneko T - Nanoscale Res Lett (2013)

The band structures of BC2N nanoribbons of the models A (a), B (b), C (c), and D (d) for N  = 8. In each panel, the result within DFT is shown in (i) and those within TB model are shown in (ii, iii, iv). Note that the center of the energy, E = 0, does not mean the Fermi level in models C and D within TB model. In (c - iv) and (d - iv), the improved band structures by adding the extra site energies at the outermost atoms are indicated by the blue dotted lines.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750270&req=5

Figure 2: The band structures of BC2N nanoribbons of the models A (a), B (b), C (c), and D (d) for N  = 8. In each panel, the result within DFT is shown in (i) and those within TB model are shown in (ii, iii, iv). Note that the center of the energy, E = 0, does not mean the Fermi level in models C and D within TB model. In (c - iv) and (d - iv), the improved band structures by adding the extra site energies at the outermost atoms are indicated by the blue dotted lines.
Mentions: The calculated band structures of BC2N nanoribbons for N = 8 are summarized in Figure2. The band structure of the model A nanoribbon within DFT shown in Figure2a(image i) have nearly degenerate band around the Fermi level. In Figure2a(images ii, iii, and iv), the band structures of the model A nanoribbons within TB model are shown. We observed that the flat bands and the degree of degeneracy depend on EB/t[24]. The band structure for EB/t = 0.7 has the doubly degenerate flat bands at E = 0, but the twofold degeneracy was lifted with increasing EB[24]. The band structure within DFT resembles to that within TB for EB/t = 1.3 shown in Figure2a(image iv). The length of the flat bands increase with increasing of EB, since the shift of the Dirac point of BC2N sheet increases[24].

Bottom Line: The zigzag BC2N nanoribbons have the flat bands when the atoms are arranged as B-C-N-C along the zigzag lines.In this arrangement, the effect of charge transfer is averaged since B and N atoms are doped in same sublattice sites.This effect is important for not only the formation of flat bands but also for the validity of the tight binding model for such system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Computational Material Science Unit, NIMS, 1-2-1 Sengen, Tsukuba 305-0047, Japan. KANEKO.Tomoaki@nims.go.jp.

ABSTRACT
: In this paper, electronic properties of BC2N nanoribbons with zigzag edges are studied theoretically using a tight binding model and the first-principles calculations based on the density functional theories. The zigzag BC2N nanoribbons have the flat bands when the atoms are arranged as B-C-N-C along the zigzag lines. In this arrangement, the effect of charge transfer is averaged since B and N atoms are doped in same sublattice sites. This effect is important for not only the formation of flat bands but also for the validity of the tight binding model for such system.

No MeSH data available.