Band structure model and dynamical dielectric function in lowest stages of graphite acceptor compounds

Blinowski, J.; Hau, Nguyen Hy; Rigaux, C.; Vieren, J. P.; Toullec, R. Le; Furdin, G.; Hérold, A.; Melin, J.

doi:10.1051/jphys:0198000410104700

Cited by 279 publications

(59 citation statements)

References 9 publications

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“…where p is the two-dimensional momentum operator and v 0 = 3γ 0 a/2 ≈ 10 6 m/s (a = 0.142 nm is the CC distance and γ 0 = 2.4 eV is the nearest neighbor tight binding overlap integral [27,28]). The Hamiltonian, Eq.…”

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confidence: 99%

Effects of spatial dispersion on the Casimir force between graphene sheets

et al. 2012

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-The Casimir force between graphene sheets is investigated with emphasis on the effect from spatial dispersion using a combination of factors, such as a nonzero chemical potential and an induced energy gap. We distinguish between two regimes for the interaction -T = 0 K and T = 0 K. It is found that the quantum mechanical interaction (T = 0 K) retains its distance dependence regardless of the inclusion of dispersion. The spatial dispersion from the finite temperature Casimir force is found to contribute for the most part from n = 0 Matsubara term. These effects become important as graphene is tailored to become a poor conductor by inducing a band gap.

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Effects of spatial dispersion on the Casimir force between graphene sheets

et al. 2012

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“…There is currently interest in the optical properties of graphene [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and graphene-based nanostructures, carbon nanotubes [21][22][23][24][25][26][27][28][29][30][31], nanoribbons [32][33][34][35], and graphene quantum dots . Graphene quantum dots are interesting because their electronic [36][37][38][39][40][41][42][43][44][45], magnetic [42,43,[46][47][48][49]…”

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confidence: 99%

Microscopic theory of the optical properties of colloidal graphene quantum dots

et al. 2014

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We present a microscopic theory of electronic and optical properties of colloidal graphene quantum dots (CGQDs). The single-particle properties are described in the tight-binding model based on the p z carbon orbitals. Electron-electron screened Coulomb direct, exchange, and scattering matrix elements are calculated using Slater p z orbitals. The many-body ground state and excited states are constructed as a linear combination of a finite number of excitations from the Hartree-Fock (HF) ground state (GS) by exact diagonalization techniques. HF ground states corresponding to semiconductor, Mott-insulator, and spin-polarized phases are obtained as a function of the strength of the screened interaction versus the tunneling matrix element. In the semiconducting phase of a triangular CGQD, the top of the valence band and the bottom of the conduction band are found to be degenerate due to rotational symmetry. The singlet and triplet exciton spectra from the HF GS are obtained by solving the Bethe-Salpeter equation. The low-energy exciton spectrum is predicted to consist of two bright-singlet exciton states corresponding to two circular polarizations of light and a lower-energy band of two dark singlets and 12 dark triplets. The robustness of the bright degenerate singlet pair against correlations in the many-body state is demonstrated as well as the breaking of the degeneracy by the lowering of symmetry of the CGQD. The band-gap renormalization, electron-hole attraction, fine structure, oscillator strength, and polarization of the exciton are analyzed as a function of the size, shape, screening, and symmetry of the CGQD. The theoretical results are compared with experimental absorption spectra.

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“…Thus the low-energy band structure of stage I GICs is identical to doped graphene resulting in a linear band dispersion close to the crossing point of the valence and conduction bands. 16,17 Experimentally, preliminary studies on ARPES of GICs were reported. 18,19 Until now the details in the low-energy quasiparticle ͑QP͒ dispersion of GICs have not been identified and the issue of whether the charge transfer to graphite is complete [20][21][22][23] or partial 18,19,24 was never resolved.…”

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Angle-resolved photoemission study of the graphite intercalation compoundKC8: A key to graphene

et al. 2009

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Electrons in isolated graphene layers are a two-dimensional gas of massless Dirac Fermions. In realistic devices, however, the electronic properties are modified by elastic deformations, interlayer coupling and substrate interaction. Here, we unravel the electronic structure of noninteracting, doped graphene layers by revisiting the stage one graphite intercalation compound KC 8 . To this end we apply angle-resolved photoemission spectroscopy and ab initio calculations. The full experimental dispersion is in excellent agreement with calculations of doped graphene once electron correlations are included at the GW level ͑Greens function G of the Coulomb interaction W͒. This highlights that KC 8 has negligible interlayer coupling allowing us to access the full experimental Dirac cone. The recent discovery of two-dimensional metastable graphene sheets has sparked enormous interest in their lowenergy electronic structure.1,2 Angle-resolved photoemission spectroscopy ͑ARPES͒ has been proven to be a key tool to determine the electronic structure of one-and few-layer graphene 3 and graphite. 4-6 A major problem for the investigation of graphene on SiC and metal substrates is that there is a significant modification of the electronic structure due to interaction with the substrates yielding charge transfer and hybridization. 7,8 Upon intercalation of Au into the graphene/ substrate interface, the Fermi level could be brought back to the Dirac point. 9 However, the graphene electronic bands are still strongly renormalized by a kink at 0.95 eV due to interaction with the Au film.9 Thus, neither graphene on SiC nor graphene on metal substrates provides access to the full Dirac cone of noninteracting graphene. One way to overcome this problem is to measure single crystalline graphite, which has no substrate interaction. In this case however, a k z dispersion of two valence bands 6 and a small gap 10 were observed because of the AB stacking of graphene layers ͑AA stacking does not show the gap opening͒.11 Another important issue is the renormalization of the bare electronic band structure due to doping-dependent electron-electron correlation, 6 electron-phonon coupling ͑EPC͒ 5,12 or electronplasmon coupling. 13In the present work, we take a different perspective to circumvent the problems of substrate interaction, strong bilayer splitting and electron-electron correlation by revisiting stage one graphite intercalation compound ͑GIC͒ KC 8 using a combination of ARPES and ab initio calculations. We show that the electronic properties of intercalated graphite and graphene are equivalent, therefore, we can use the former to understand the physics of the latter. In particular, we provide the full experimental Dirac cone of doped graphene layers in KC 8 using ARPES. We compare the ARPES intensities to ab initio calculations and find good agreement with calculations at the GW level. In contrast to previous works on undoped graphite 6 and graphene monolayers on metal substrates 7,14 the electronic energy band structure of graphene sh...

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Band structure model and dynamical dielectric function in lowest stages of graphite acceptor compounds

Cited by 279 publications

References 9 publications

Effects of spatial dispersion on the Casimir force between graphene sheets

Effects of spatial dispersion on the Casimir force between graphene sheets

Microscopic theory of the optical properties of colloidal graphene quantum dots

Angle-resolved photoemission study of the graphite intercalation compoundKC8: A key to graphene

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