Substrate effects on transport properties of a biased AA-stacked bilayer graphene

Abstract

The important experimental advances in graphene fabrication and its peculiar transport properties motivated researchers to utilize graphene as a potential basis for the next generation of fast and smart electronic devices. In this article, we investigate the influence of a potential substrate on the transport properties of a biased AA-stacked n-p-n bilayer graphene junction (AA-BLG). Using the Dirac Hamiltonian with the transfer matrix approach we obtain the transmission probabilities and thus the respective conductance. In the presence of the induced mass-term the energy spectrum and the intra-cone transmission drastically change while the inter-cone transmission remains zero. On the other hand, the bias slightly alters the energy spectrum but it significantly affects the transport properties due to its ability to switch on the inter-cone transmission. In addition, we find that Klein tunnelling is attenuated in the presence of the induced mass-term which can improve the carriers confinement in such configurations. Our findings provide possible experimental measurements to determine the interlayer coupling and the induced mass terms in graphene bilayer based on conductance and band structure measurements.PACS numbers:

Transport Properties in Gapped Bilayer Graphene

“…This con- firms that our ∆ 0 has a significant impact on the transport properties and differs from that induced by bias in AB-BLG [29]. Instead of contrast, the total conductance of a gapped AA-BLG is approximately unchanged even though the band gap has a significant impact on the intracone transport [43]. Now we involve both of parameters by presenting Figs 7(b) and 7(c) corresponding, respectively, to ∆ 0 = δ = 0.3γ 1 , and ∆ 0 = 0.5γ 1 , δ = 0.3γ 1 .…”

“…, because the incident electrons back again in an electron state [29]. This is not the case for gapped AA-BLG, whereas T + − and T − + channels preserve the momentum symmetry [43]. In addition, there is a significant distinction for all reflection channels, R s ± , between gapped AB-BLG and biased AB-BLG.…”

Band gap engineering in AA-stacked bilayer graphene

“…4 (right panel). On the other hand, the profile of the inter-cone transmission (T + − = T − + ) shows finite transport within the same energy ranges rendering charge carriers in the system unconfined 49 . The propagating modes interfere with themselves in the interaction region as a result of the finite size effect.…”

“…As discussed in the preceding sections, scattering between the lower and upper cones can be induced only by inter-layer bias or inter-layer mass difference. The effect of the mass-term amplitude on the transport properties and Klein tunneling in unbiased 48 and biased 49 AA-BLG has been studied before. Here we briefly discuss the results of a biased AA-BLG in the presence of the mass-term amplitude to compare the strength of inter-cone scattering with the one arisen by the interlayer mass-term difference.…”

“…They are arising as a result of the cones coupling established by the bias, see Eq. 2, and they completely vanish once the two cone are decoupled 49 .…”