Effective mass versus band gap in graphene nanoribbons: influence of H-passivation and uniaxial strain

Abstract

A simple model which combines tight-binding (TB) approximation with parameters derived from first principle calculations is developed for studying the influence of edge passivation and uniaxial strain on electron effective mass of armchair graphene nanoribbons (AGNRs). We show that these effects can be described within the same model Hamiltonian by simply modifying the model parameters i.e., the hopping integrals and onsite energies. Our model reveals a linear dependence of effective mass on band gap for H-passivated AGNRs for small band gaps. For large band gap, the effective mass dependence on band gap is parabolic and analytic fits were derived for AGNRs belonging to different families. Both band gap and effective mass exhibit a nearly periodic zigzag variation under strain, indicating that the effective mass remains proportional to the band gap even when strain is applied. Our calculations could be used for studying carrier mobility in intrinsic AGNRs semiconductors where carrier scattering by phonons is the dominant scattering mechanism.