Quantum transport across van der Waals domain walls in bilayer graphene

Abstract

Bilayer graphene can exhibit deformations such that the two graphene sheets are locally detached from each other resulting in a structure consisting of domains with different van der Waals inter-layer coupling. Here we investigate how the presence of these domains affects the transport properties of bilayer graphene. We derive analytical expressions for the transmission probability, and the corresponding conductance, across walls separating different inter-layer coupling domains. We find that the transmission can exhibit a valley-dependent layer asymmetry and that the domain walls have a considerable effect on the chiral tunnelling properties of the charge carriers. We show that transport measurements allow one to obtain the strength with which the two layers are coupled. We perform numerical calculations for systems with two domain walls and find that the availability of multiple transport channels in bilayer graphene significantly modifies the conductance dependence on inter-layer potential asymmetry.

Electron collimation at van der Waals domain walls in bilayer graphene

“…To describe electron dynamics semi-classically one proceeds in two steps. We first use the quantum mechanical formalism to evaluate transmission and reflection probabilities 38,[57][58][59] , and secondly determine the electron trajectories using the classical approach. Since the system is invariant along the x−direction, the solution of the Schrödinger equation HΨ = EΨ can be written in a matrix form as…”

“…The symmetric and antisymmetric components correspond to the k + and k − energy bands (For more details see Refs. [38]). In our results for AA-BLG case, we use the above wave function to calculate the center mass position and the probability amplitudes.…”

“…1(e) and (f), respectively. Recently, it was shown that such systems exhibit distinct electronic properties [38][39][40][41][42][43] . In the lowenergy regime, the Fermi circle in delaminated region is much smaller than its counterpart in the AA-BLG.…”

Band gap engineering in AA-stacked bilayer graphene

“…The presence of the gap in this case is a manifestation of breaking the inversion symmetry. In AA-BLG all atoms take part in the interlayer coupling contrary to the AB-BLG where only half of the atoms participate and as a consequence γ AB 1 = 2γ AA 1 ≈ 0.4 eV [43][44][45] . Another difference is that the latter has asymmetric interlayer coupling, in other words, atom A 1 coupled to atom B 2 while the coupling is symmetric in the AA-BLG.…”

Crossed graphene nanoribbons as beam splitters and mirrors for electron quantum optics

“…We first discuss the effect of small rotations of the on-top ribbon starting from the ideal configuration where θ = 60 • . For instance, the twisting angle between the ribbons introduces separated domains of weakly and strongly coupled atoms in the crossing area that might affect the transport properties of these junctions [68]. To isolate the effect of the intersection angle from that of the precise stacking pattern (translation), we apply the rotation around the center of the scattering region (crossing) indicated with a black dot in Fig.…”