When a single layer graphene is epitaxially grown on silicon carbide,it will exhibit a finite energy gap like a conventional semiconductor,and its energy dispersion is no longer linear in momentum in the low energy regime.In this paper,we have investigated the tunneling characteristics through a two-dimensional barrier in a single layer graphene with an energy gap.It is found that when the electron is at a zero angle of incidence,the transmission probability as a function of incidence energy has a gap.Away from the gap the transmission coefficient oscillates with incidence energy which is analogous to that of a conventional semiconductor.The conductance under zero temperature has a gap.The properties of electron transmission may be useful for developing graphene-based nano-electronics.
We examine the temperature dependence of acoustic-phonon-induced magnetoresistance oscillations in a high-mobility GaAs-based quantum well with conventional transverse and longitudinal phonon modes,using a model in which the temperature increase of the Landau level broadening or the single-particle scattering rate 1/τ_s is attributed to the enhancement of electron-phonon scattering with rising temperature.The non-monotonic temperature behavior, showing an optimal temperature at which a given order of oscillation amplitude exhibits a maximum and the shift of the main resistance peak to higher magnetic field with rising temperature,is produced,in agreement with recent experimental findings.
