Coulomb Excitations and Decays in Graphene-Related Systems

Abstract

The layered graphene systems exhibit the rich and unique excitation spectra arising from the electron-electron Coulomb interactions. The generalized tight-binding model is developed to cover the planar/buckled/cylindrical structures, specific lattice symmetries, different layer numbers, distinct configurations, one-three dimensions, complicated intralayer and interlayer hopping integrals, electric field, magnetic quantization; any temperatures and dopings simultaneously. Furthermore, we modify the random-phase approximation to agree with the layer-dependent Coulomb potentials with the Dyson equation, so that these two methods can match with other under various external fields. The electron-hole excitations and plasmon modes are greatly diversified by the above-mentioned critical factors; that is, there exist the diverse (momentum. frequency)-related phase diagrams. They provide very effective deexcitation scatterings and thus dominate the Coulomb decay rates. Graphene, silicene 1 arXiv:1901.04160v1 [physics.comp-ph] 14 Jan 2019 and germanene might quite differ from one another in Coulomb excitations and decays because of the strength of spin-orbital coupling. Part of theoretical predictions have confirmed the experimental measurements, and most of them require the further examinations. Comparisons with the other models are also made in detail.

Na-intercalation compounds and Na-ion batteries

“…The multi-/singleorbital hybridizations in different chemical bonds are determined by unifying the relevant quantities; that is, the critical quasiparticle pictures are reached through the full cooperation of the atom-dominated band structures, the charge density distributions, and the orbital-decomposed van Hove singularities. These will be very useful in establishing the concise phenomenological models, e.g., the tight-binding model [118][119][120]/the generalized tightbinding model [114,121] in the absence/presence of a perpendicular magnetic field for the rich magnetic quantization phenomena [112,114,119].…”

Electronic and optical properties of graphene, silicene, germanene, and their semi-hydrogenated systems

“…2,3 Beyond graphene, the other famous group-IV monolayers include silicene, 4 germanene, 5 tinene, 6 and plumbene 7 and it's hydrogenated systems. 8,9 Such layered systems are ideal for studying a variety of physical, chemical, and material phenomena, [10][11][12] mainly owing to rich and unique intrinsic atomic interactions and geometric symmetries.…”

Optical scatterings in layered systems

“…The systematic investigations for the diversified magnetic quantization have been done for 2D materials [4,5], such as, the unusual Landau levels and magnetooptical selection rules. This theoretical framework is useful in fully understanding the electronic [1,2], magnetic [5,8], optical [4][5][6][7][8][9][10][11][12], transport [13] and Coulomb-excitation [14] properties under the intrinsic atomic interactions and field perturbations. However, the Kubo formula is not enough in exploring reflectance and transmittance spectra of thin films with prominent boundary effects.…”

“…The π-electronic states of sp 2 -bonding systems [1][2][3] are responsible for the essential properties, such as, graphenes [1,15], carbon nanotubes [16][17][18], graphene nanoribbons [19][20][21], onions [22,23] and fullerenes [24,25]. Very interesting, such carriers dominate the dynamic/static screening responses under the significant perturbation of an electromagnetic/Coulomb field [4,14], as clearly revealed in rich absorption spectra of few-layer graphene systems [8][9][10]. The inter-π-band transitions, which correspond to the occupied valence subbands and the unoccupied conduction ones, can absorb photon energies and thus induce an obvious decline of a propagating EM wave.…”

“…The close relations between charges and fields are well characterized by the transverse dielectric function [26]. (ω ) of a multi-/few-layer graphene system will be evaluated under the generalized tight-binding model [14], being suitable under perpendicular gate voltages and uniform magnetic fields.…”