Electronic properties of rhombohedral graphite

Wong, Jen-Hsien; Wu, Bi-Ru; Lin, Ming-Fa

doi:10.1016/j.cpc.2010.07.030

Cited by 7 publications

(4 citation statements)

References 39 publications

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“…As compared to the bulk bands of rhombohedral graphite with DFT 7,[23][24][25] and tight binding 25 calculations, and to the evolution of graphene to graphite with tight binding calculation 19 , it is clear that these states are surface states of the few-layer rhombohedral graphene. In order to understand the amount of charge needed to fill the flat surface band and close the gap, we have integrated first peak of the density of states above the gap.…”

Section: Appendix C: Metallic and Paramagnetic Bandsmentioning

confidence: 99%

Magnetic gap opening in rhombohedral-stacked multilayer graphene from first principles

et al. 2017

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We investigate the occurrence of magnetic and charge density wave instabilities in rhombohedralstacked multilayer (three to eight layers) graphene by first principles calculations including exact exchange. Neglecting spin-polarization, an extremely flat surface band centered at the special point K of the Brillouin zone occurs at the Fermi level. Spin polarization opens a gap in the surface state by stabilizing an antiferromagnetic state. The top and the bottom surface layers are weakly ferrimagnetic in-plane (net magnetization smaller than 10 −3 µB), and are antiferromagnetic coupled to each other. This coupling is propagated by the out-of-plane antiferromagnetic coupling between the nearest neighbors. The gap is very small in a spin-polarized generalized gradient approximation, while it is proportional to the amount of exact exchange in hybrid functionals. For trilayer rhombohedral graphene it is 38.6 meV in PBE0, in agreement with the 42 meV gap found in experiments. We study the temperature and doping dependence of the magnetic gap. At electron doping of n ∼ 7 × 10 11 cm −2 the gap closes. Charge density wave instabilities with √ 3 × √ 3 periodicity do not occur.In a solid, at low enough density, the Coulomb energy dominates the single particle energy and electronic instabilities such as magnetic phases or even Wigner crystallization become possible. A reduction of the singleparticle energy, and a consequent enhancement of the electron-electron interaction, can be obtained by considering a metallic system with a very flat single-particle band-dispersion. This unfortunately does not happen in graphene where the high Fermi velocity prevents electronic instability. The situation is different, however, in weakly doped Bernal-stacked (AB) even-multilayer graphene (see Fig. 1), as the single-particle bands become massive. Indeed, a spontaneously gapped ground state is already observed in suspended bilayer 1,2 and fourlayer graphene (1.5 meV gap) 3 .Even more favorable to electronic instabilities is rhombohedral-stacked (ABC) multilayer graphene. Neglecting spin polarization, tight-binding and density functional theory (DFT) calculations find bulk rhombohedral graphite to be metallic with a high Fermi velocity (see grey region in Fig. 1). On the contrary, within these approximations, rhombohedral-stacked multilayer graphene (RSMG) displays the occurrence of an extremely flat surface state at the Fermi level (see Fig. 1) located at the K point of the graphene Brillouin zone (BZ) 4-9 . The extension of the surface state in the BZ increases with increasing thickness and saturates at ≈ 7 layers. Its bandwidth is at most 2 meV for flakes of fewer than eight layers. The extremely reduced bandwidth makes RSMG one of the strongest correlated systems known nowadays and an ideal candidate for correlated states even in the absence of d orbitals.On the experimental side, only recently has it been possible to synthesize RSMG. Ouerghi et al.10 found fivelayer RSMG on top of a cubic SiC substrate to be metallic with a very high d...

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Section: Appendix C: Metallic and Paramagnetic Bandsmentioning

confidence: 99%

Magnetic gap opening in rhombohedral-stacked multilayer graphene from first principles

et al. 2017

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“…However, it was recently shown that even "graphene flakes" can generate 2D bands composed of more than one Lorentzian fitting component [28]. The interlayer distance in graphite equals to about 0.335 nm [29] and slightly varies with stacking order [30]. Since the processes of migration of carbon atoms from SiC interface and decomposition of silicon-carbide substrate are going simultaneously one should not expect drastic change of the thickness of deposited carbon layer.…”

Section: Profile Number Nsc1 1 N S C 1 3 N S C 1mentioning

confidence: 99%

Visible and Deep-Ultraviolet Raman Spectroscopy as a Tool for Investigation of Structural Changes and Redistribution of Carbon in Ni-Based Ohmic Contacts on Silicon Carbide

et al. 2012

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Three samples of 4H polytype of silicon carbide (4H-SiC) covered with the following sequence of layers: carbon/nickel/silicon/nickel/silicon were investigated with micro-Raman spectroscopy. Different thermal treatments of each sample result in differences of carbon layer structure and migration of carbon atoms thorough silicide layer. Two ranges of Raman shift were investigated. The first one is placed between 1000 cm−1 and 2000 cm−1. The main carbon bands D and G are observed in this range. Analysis of the positions of these bands and their intensity ratio enables one to determine the graphitization degree of carbon layer. Additional information about the changes of the carbon layer structure was derived from analysis of 2D band placed around 2700 cm−1. Application of deep ultraviolet excitation delivered information about the structure of carbon layer formed on the free surface of silicides and the distribution of the carbon inside the silicide layer.

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“…Before a further discussion on the other physical properties in the present study, we made a comparison in the energy dispersions between TB and FP theories carefully (Fig. 2 and 3), 54 examining if the atomic interactions are suitable in TB model or not. It shows a good agreement in low energy, such as Fermi velocity, band-edge states, degeneracy, k z dependence, overlaps between the conduction and valence bands, linear and parabolic bands with and without degeneracy, anisotropic dispersion, and its semimetal property.…”

Section: Energy Dispersionsmentioning

confidence: 99%

Low-frequency electronic and optical properties of rhombohedral graphite

Chiu

Huang

Chen

et al. 2011

Phys. Chem. Chem. Phys.

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Low-energy electronic and optical properties of ABC-stacked graphite are respectively studied by the tight-binding model and gradient approximation. The band structures include linear and parabolic bands with and without degeneracy. They show strongly anisotropic dispersions. ABC-stacked graphite is a semimetal due to the slight overlap near the Fermi level between the conduction and valence bands. The interlayer interactions change the energy dispersion, state degeneracy, and the positions of band-crossings and band-edge states. When the state energy is higher than the degenerate energy of the conduction band (E(2d)(c)) or lower than that of the valence bands (E(2d)(v)), a greater number of states might exist. The special band structures would be reflected in the density of states (DOS), the joint density of states (JDOS), and the absorption spectra (A(ω)). For example, the DOS exhibits a cave-like structure at ω = E(2d)(c) and E(2d)(v). Both a special jump in the JDOS and a turning point in the A(ω) occur at ω = E(2d)(c) - E(2d)(v). The DOS and A(ω) could be respectively verified by scanning tunneling spectroscopy and optical absorption spectroscopy.

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Electronic properties of rhombohedral graphite

Cited by 7 publications

References 39 publications

Magnetic gap opening in rhombohedral-stacked multilayer graphene from first principles

Magnetic gap opening in rhombohedral-stacked multilayer graphene from first principles

Visible and Deep-Ultraviolet Raman Spectroscopy as a Tool for Investigation of Structural Changes and Redistribution of Carbon in Ni-Based Ohmic Contacts on Silicon Carbide

Low-frequency electronic and optical properties of rhombohedral graphite

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