Rich magneto-absorption spectra of AAB-stacked trilayer graphene

Abstract

A generalized tight-binding model is developed to investigate the feature-rich magneto-optical properties of AAB-stacked trilayer graphene. Three intragroup and six intergroup inter-Landau-level (inter-LL) optical excitations largely enrich magneto-absorption peaks. In general, the former are much higher than the latter, depending on the phases and amplitudes of LL wavefunctions. The absorption spectra exhibit single- or twin-peak structures which are determined by quantum modes, LL energy spectra and Fermion distribution. The splitting LLs, with different localization centers (2/6 and 4/6 positions in a unit cell), can generate very distinct absorption spectra. There exist extra single peaks because of LL anti-crossings. AAB, AAA, ABA, and ABC stackings considerably differ from one another in terms of the inter-LL category, frequency, intensity, and structure of absorption peaks. The main characteristics of LL wavefunctions and energy spectra and the Fermi-Dirac function are responsible for the configuration-enriched magneto-optical spectra.

Coulomb Excitations and Decays in Graphene-Related Systems

“…Although the ABC stacking is a semimetal with a very low free carrier density, it is predicted to exhibit the low-frequency plasmom mode closely related to the localized states [29]. Fur-comparison between the tight-binding model and VASP calculations in the low-lying energy bands [84,85]. For example, the AAB-stacked trilayer graphene exhibits three pairs of energy bands with the oscillatory, sombrero-shaped and parabolic dispersions, in which the first ones determine a very band gap of < 10 meV.…”

Introduction

“…Regarding the latter, one can use optical spectroscopy to identify the non-monotonic changes in the structures, frequencies, intensities and numbers of the absorption peaks [175]. This phenomenon is expected to be more significant in low-symmetry AAB-stacked and sliding bilayer graphene [65,66]. In sufficiently low magnetic fields, the spectral features reflect the band structures, such as the symmetry, energy dispersions and atomic interactions, as well as the broken mirror symmetry under the electric field.…”

“…On the other hand, a magnetic field gives rise to interesting Landau quantization phenomena in the electronic and optical properties of odd-layer symmetry-broken graphene and evenlayer inversion-symmetry graphene [126, 128-131, 141, 142]. Massless and massive Dirac quasi-particles reveal single-and twin-peak structures, respectively, in the monolayer-like and bilayer-like spectra [65,158]. The corresponding ratio of the peak intensities is estimated to be about 2:1.…”

“…The improved quality is adequate for research experiments and industrial applications [41][42][43][44][45][46][47][48][49]. In addition, AAB stacking and intermediate bilayer configurations, with relative layer-layer shifts or twists, have also been found and are becoming interesting subjects [59][60][61][62][63][64][65][66][67]. Synthesized graphene is generally comprised of different kinds of domain due to the tiny difference between the total energies of the different configurations.…”

“…AA [78][79][80], AB [81][82][83][84][85][86][87][88][89][90][91][92][93], ABC [93][94][95][96][97][98][99] and AAB [64], are predicted to display unique electronic energy dispersions. This new material holds great promise for the development of next-generation electronic and optoelectronic nanodevices [41-47, [50][51][52][53][54][55][56] because the electronic and optical properties can be flexibly tuned by the application of external fields [64][65][66][67][68][69][70][71][72][73][74] as well as changes to the geometric structures and dopants [115][116][117][118][119][120]…”