Effect of chiral property on hot phonon distribution and energy loss rate due to surface polar phonons in a bilayer graphene

Abstract

Effect of chiral property on hot phonon distribution and hot electron energy loss rate due to surface polar phonons is investigated in a supported bilayer graphene. Hot phonon distribution Nq(ω0) with chiral property shows a new feature of appearance of a cusp. Interestingly, minimum of the cusp is shifting toward larger q and its width is increasing as electron concentration ns increases. The maximum value of Nq(ω0) is found to shift toward lower q with the increasing ns. This unusual behavior is not found in conventional two-dimensional electron gas (2DEG). The effect of chiral property on energy loss rate is found to be less significant. Hot phonon effect on energy loss rate is studied as a function of electron temperature and electron concentration for different substrates. It is found to reduce the energy loss rate significantly and the results are compared with those in conventional 2DEG. We believe that the magnitude of hot phonon effect depends both on dielectric constant of the substrate and surface polar phonon energy.