Negative differential resistance in armchair silicene nanoribbons

Due to dimensional confinement of carriers and non-trivial changes in the electronic structure, novel tunable transport properties manifest in nanoscale materials. Here, we report using firstprinciples density functional theory and non-equilibrium Green's function formalism, the occurrence of negative differential resistance (NDR) in armchair silicene nanoribbons (ASNRs). Interestingly, NDR manifests only in pristine 3n + 2 ASNRs, where n ∈ Z⁺. We show that the origin of such a novel transport phenomenon lies in the bias-induced changes in the density of states of this particular family of nanoribbons. With increasing width of the nanoribbons belonging to this family, the peak-to-valley ratios of current decrease due to the increase in the number of sub-bands leading to a reduction in NDR. NDR is possible not only in 3n + 2 ASNRs, but also in mixed configurations of armchair and zigzag silicene nanoribbons. This universality of NDR along with its unprecedented width-induced tunability can be useful for silicene-based low-power logic and memory applications.