Suppression of localized transmission peaks and deviation from Matthiessen's rule in disordered armchair graphene nano-ribbons due to acoustic phonons

Abstract

The electronic properties of armchair edge graphene nanoribbons (AGNRs) in the presence of disorders such as edge roughness, and vacancy are studied based on the non-equilibrium Green's function formalism. Elastic electron–phonon scattering is also included in our study. AGNRs with disorder exhibit localized transmission peaks in the transport band-gap. These localized peaks contribute to unwanted electron transport and conductivity of AGNRs. Results of our numerical simulations show that these states are extremely unstable and sensitive to lattice vibrations and are suppressed by acoustic phonons at room temperature. It was also found that the resistivity of AGNRs due to acoustic phonons and disorders, especially in the case of off-states, deviates from the values predicted using Matthiessen's rule where the effect of each scattering mechanism is considered separately. According to the results, deviation from Matthiessen's rule become more severe with the increase in the strength of disorder and AGNR length.