Signature of quantum interference and the Fano resonances in the transmission spectrum of bilayer graphene nanostructure

Abstract

The well-known asymmetric Fano resonances that results from the quantum interference between the discrete and the continuum states are noted for the first time in the ballistic transmission spectrum of the bilayer graphene tunneling structures. This unconventional tunneling transmission, in stark contrast to the monolayer graphene and to the conventional heterostructures, arises due to the quadratic dispersion of the chiral charge carriers. If the Klein tunneling (the phenomenon for normal incidence) is an unusual characteristic of the massless chiral particles, then the Fano tunneling (the phenomenon for low glancing incidence) would be the specialty for the massive chiral particles. The characteristic features of the Fano line shape are found to be highly sensitive to the direction of incidence of the charge carriers, the applied homogeneous electric field, and to the barrier height. The sharp anti-resonance at the center of the tunneling band arising due to the destructive interference between the electron and the holelike states could probably be responsible for the high negative differential conductance (NDC) in the bilayer graphene. The tunneling conductance in the double barrier structure exhibits a resonant peak with a sharp NDC region for the Fermi energy less than or equal to half of the barrier height. The present findings might have great implications in the preparation of NDC-based devices using bilayer graphene nanostructures.

Fano resonance in novel plasmonic nanostructures

“…Recently, Fano interferences have been applied successfully to explain a large number of phenomena in various systems. These phenomena include the quantum transport in quantum dots, wires and tunnel junctions , the energy‐dependent line profile of absorption in molecular systems , bilayer graphene nanostructures and the asymmetric distribution of the density of states in Anderson impurity systems as well as several optical systems, such as strong coupling between Mie and Bragg scattering in photonic crystals and terahertz metamaterials .…”

Hybrid matrix method for stable numerical analysis of the propagation of Dirac electrons in gapless bilayer graphene superlattices

“…where ψ 1 (x, y)/ ψ 2 (x, y) is the two component pseudo-spin wavefunction for the graphene sublattice A / B [21,28]. Considering the conservation of the transversal momentum (q y ) the wavefunction (17) can be expressed as:…”

“…One of the most remarkable differences of gapless bilayer graphene as compared with gapless monolayer graphene is that propagating and evanescent states coexist inherently in this material, giving rise to quite interesting and exotic phenomena such as anti-Klein tunneling [6] and Fano resonances [28,29,30]. The case of Fano resonances in GBG is unique, since in practically all material systems in which this phenomenon is manifested an external source that provides extended states is required [31,32].…”

“…where q x and q y are the quasiparticle wavevectors along the x and y directions respectively; m is the band effective mass taken as 0.035 m 0 , and m 0 is the bare electron mass [8,28,30].…”

“…In GBG this mixture is given by the presence of evanescent-divergent states in the eigenfunctions linear superposition representing the Dirac spinors. Due to the peculiarities presented in this material [6,28,29,30] the Ωd problem is more likely in GBG superlattice studies where param-eters such as the energy and angle of the incidence electrons as well as the thickness and number of barriers is increased. Likewise, in aperiodic or quasi-periodic structures this numerical degradation is natural, since the size of these structures increases as a function of the generation number [41,42].…”