Bias free gap creation in bilayer graphene

Davenport, A. R.; Hague, J. P.

doi:10.1088/0953-8984/26/22/225601

Cited by 2 publications

(1 citation statement)

References 45 publications

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“…The choice of substrate/superstrate is therefore expected to make little difference to the gap in biased bilayer graphene, which remains relatively small. We note that this is not contrary to our previous results on gap opening in unbiased graphene [28], rather that the presence of large applied potential difference between layers overwhelms the effects of the small Coulomb induced inhomogeneity that is responsible for gap opening in the unbiased case.…”

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confidence: 99%

Role of substrate induced electron–phonon interactions in biased graphitic bilayers

Davenport¹,

Hague²

2016

J. Phys.: Condens. Matter

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Bilayers of graphitic materials have potential applications in field effect transistors (FETs). A potential difference applied between certain ionic bilayers made from insulating graphitic materials such as BN, ZnO and AlN could reduce gap sizes, turning them into useful semiconductors. On the other hand, opening of a small semiconducting gap occurs in graphene bilayers under applied field. The aim here is to investigate to what extent substrate induced electron-phonon interactions (EPIs) modify this gap change. We examine EPIs in several lattice configurations of graphitic bilayers, using a perturbative approach. The typical effect of EPIs on the ionic bilayers is an undesirable gap widening. The size of this gap change varies considerably with lattice structure and the magnitude of the bias. When bias is larger than the non-interacting gap size, EPIs have the smallest effect on the bandgap, especially in configurations with [Formula: see text] and AB structures. Thus careful selection of substrate, lattice configuration and bias strength to minimise the effects of EPIs could be important for optimising the properties of electronic devices. We use parameters related to BN in this article. In practice, the results presented here are broadly applicable to other graphitic bilayers, and are likely to be qualitatively similar in metal dichalcogenide bilayers such as MoS2, which are already of high interest for their use in FETs.

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Section: Discussioncontrasting

confidence: 99%

Role of substrate induced electron–phonon interactions in biased graphitic bilayers

Davenport¹,

Hague²

2016

J. Phys.: Condens. Matter

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Theoretical study of modified electron band dispersion and density of states due to high frequency phonons in graphene-on-substrates

Sahu

Rout

2018

Int. J. Comp. Mat. Sci. Eng.

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We propose here a theoretical model for the study of band gap opening in graphene-on- polarizable substrate taking the effect of electron–electron and electron–phonon (EP) interactions at high frequency phonon vibrations. The Hamiltonian consists of hopping of electrons upto third nearest- neighbors and the effect substrate, where A sublattice site is raised by energy [Formula: see text] and B sublattice site is suppressed by energy [Formula: see text], hence producing a band gap energy of [Formula: see text]. Further, we have considered Hubbard type electron–electron repulsive interactions at A and B sublattices, which are considered within Hartree–Fock meanfield approximation. The electrons in the graphene plane interact with the phonon’s present in the polarized substrate in the presence of phonon vibrational energy within harmonic approximation. The temperature-dependent electron occupancies are computed numerically and self-consistently for both spins at both the sublattice sites. By using these electron occupancies, we have calculated the electron band dispersion and density of states (DOS), which are studied for the effects of EP interaction, high phonon frequency, Coulomb energy and substrate induced gap.

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Bias free gap creation in bilayer graphene

Cited by 2 publications

References 45 publications

Role of substrate induced electron–phonon interactions in biased graphitic bilayers

Role of substrate induced electron–phonon interactions in biased graphitic bilayers

Theoretical study of modified electron band dispersion and density of states due to high frequency phonons in graphene-on-substrates

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