Tuning field-induced energy gap of bilayer graphene via interlayer spacing

Guo, Yufeng; Guo, Wanlin; Chen, Changfeng

doi:10.1063/1.2943414

Cited by 102 publications

(77 citation statements)

References 25 publications

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“…5͑b͔͒ consistent with earlier density-functional results. 13,14 The magnitude of the band gap increases linearly for small electric fields and saturates for higher electric fields as seen from Fig. 5͑d͒.…”

Section: Bilayer Graphene In the Bernal Structurementioning

confidence: 66%

“…11,12 Hence, a uniaxial strain, which changes the interlayer spacing, could modulate the field-induced band gap. 13,14 The other factor that controls the gap is the screening of the electric field. An applied electric field causes unequal charge distribution among the graphene layers which in turn creates a polarized electric field in the opposite direction, 7 thereby reducing the effective electric field.…”

Section: Introductionmentioning

confidence: 99%

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Strain and electric field modulation of the electronic structure of bilayer graphene

Nanda

Satpathy

2009

Phys. Rev. B

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We study how the electronic structure of the bilayer graphene ͑BLG͒ is changed by electric field and strain from ab initio density-functional calculations using the linear muffin-tin orbital and the linear augmented plane wave methods. Both hexagonal and Bernal stacked structures are considered. We only consider interplanar strain where only the interlayer spacing is changed. The BLG is a zero-gap semiconductor like the isolated layer of graphene. We find that while strain alone does not produce a gap in the BLG, an electric field does so in the Bernal structure but not in the hexagonal structure. The topology of the bands leads to Dirac circles with linear dispersion in the case of the hexagonally stacked BLG due to the interpenetration of the Dirac cones, while for the Bernal stacking, the dispersion is quadratic. The size of the Dirac circle increases with the applied electric field, leading to an interesting way of controlling the Fermi surface. The external electric field is screened due to polarization charges between the layers, leading to a reduced size of the band gap and the Dirac circle. The screening is substantial in both cases and diverges for the Bernal structure for small fields as has been noted by earlier authors. As a biproduct of this work, we present the tight-binding parameters for the free-standing single layer graphene as obtained by fitting to the density-functional bands, both with and without the slope constraint for the Dirac cone and keeping the hopping integral up to four near neighbors.

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Section: Bilayer Graphene In the Bernal Structurementioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Strain and electric field modulation of the electronic structure of bilayer graphene

Nanda

Satpathy

2009

Phys. Rev. B

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“…Another route to open the gap is more practical to break the symmetry between sublattice in graphene by setting it onto a solid substrate or in applied fields. [12][13][14][15] A single-layer graphene on most of the substrates becomes a trivial buffer layer due to the breaking of the hexagonal π-orbital network as a result of strong bonding to the supports, [16][17][18] and a second layer is often necessary to be functional on a substrate. Although these routes are helpful for certain applications, none of them consider the essential interaction between the graphene edge and the substrate.…”

mentioning

confidence: 99%

Electronic properties of zigzag graphene nanoribbons on Si(001)

Zhang

Guo

2009

Applied Physics Letters

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We show by first-principles calculations that the electronic properties of zigzag graphene nanoribbons (Z-GNRs) adsorbed on Si(001) substrate strongly depend on ribbon width and adsorption orientation. Only narrow Z-GNRs with even rows of zigzag chains across their width adsorbed perpendicularly to the Si dimer rows possess an energy gap, while wider Z-GNRs are metallic due to width-dependent interface hybridization. The Z-GNRs can be metastably adsorbed parallel to the Si dimer rows, but show uniform metallic nature independent of ribbon width due to adsorption induced dangling-bond states on the Si surface.

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“…This is because that E g and E and ∆, respectively. 22,41 ∆ is the potential difference between the upper and bottom layers and obviously increases as a function of electric fields. t ′ is the interlayer hopping between the direct atoms.…”

Section: Resultsmentioning

confidence: 99%

Intra- and inter-layer charge redistribution in biased bilayer graphene

et al. 2016

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We investigate the spatial redistribution of the electron density in bilayer graphene in the presence of an interlayer bias within density functional theory. It is found that the interlayer charge redistribution is inhomogeneous between the upper and bottom layers and the transferred charge from the upper layer to the bottom layer linearly increases with the external voltage which further makes the gap at K point linearly increase. However, the band gap will saturate to 0.29 eV in the strong-field regime, but it displays a linear field dependence at the weak-field limit. Due to the AB-stacked way, two carbon atoms per unit cell in the same layer are different and there is also a charge transfer between them, making the widths of π valence bands reduced. In the bottom layer, the charge transfers from the direct atoms which directly face another carbon atom to the indirect atoms facing the center of the hexagon on the opposite layer, while the charge transfers from the indirect atoms to the direct atoms in the upper layer. Furthermore, there is a diploe between the upper and bottom layers which results in the reduction of the interlayer hopping interaction.

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Tuning field-induced energy gap of bilayer graphene via interlayer spacing

Cited by 102 publications

References 25 publications

Strain and electric field modulation of the electronic structure of bilayer graphene

Strain and electric field modulation of the electronic structure of bilayer graphene

Electronic properties of zigzag graphene nanoribbons on Si(001)

Intra- and inter-layer charge redistribution in biased bilayer graphene

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