Computational study of negative differential resistance in graphene bilayer nanostructures

Tunneling conductance of telescopic contacts between graphene layers with and without dielectric spacer

“…(iii) The peak-to-valley ratio I p =I v for the first peak is nearly stationary when it is observed at sufficiently high voltages (or equivalently small overlap lengths) but decreases drastically when the peak position U p approaches 0.2-0.4 V ( Table 1). The similar trends were observed previously for metallic armchair nanoribbons [14,15]. (iv) The initial slopes of all the I-U curves at low voltage (U !…”

“…These oscillations imply that there are voltage intervals with a strongly pronounced negative differential resistance, the same as in previous calculations for graphene nanoribbons [14,15,17]. Such a behavior is known to originate from the interference of carrier paths through the quasilocalized states in the bilayer region [16,17] or from Fabry-Pérot-like interference of one propagating channel with itself [16].…”

“…As for carbon-based nanoscale systems, up to now the negative differential resistance have been predicted for very narrow graphene nanoribbons [23], chemically doped [24] and field-effect doped [25] graphene nanoribbons, doped graphene monolayer with p-n junction [26], parallel graphene nanoribbons contacts [14,15] and parallel single-walled carbon nanotube contacts [27]. Here the negative differential resistance is found for contacts between graphene layers both with and without the argon spacer.…”

“…The potential energies of all carbon atoms within the graphene layers are assumed to be shifted by AEU=2 [14,15].…”

“…Significant variations in the band gap of bilayer graphene nanoribbons upon atomic-scale in-plane relative displacement of their layers are found using density functional theory (DFT) calculations [11,12]. Quasi one-dimensional transport in systems consisting of two overlapping layers [13][14][15][16][17] or a layer with an adsorbed graphene flake [16,18,19], both with a central bilayer region, has been recently a subject of extensive research. The tunneling conductance of such systems based on nanoribbons is found to change by an order of magnitude upon atomic-scale in-plane relative displacement of the layers [13].…”