▎ 摘　　要

We investigate the scattering efficiency of carriers with optical phonons in Landau-quantized graphene within a microscopic theory. Strong carrier-phonon scattering is induced, if the transition energy between Landau levels is in resonance with the constant energy of the respective optical phonon mode. Here, we study the phonon-induced scattering rate as a function of magnetic field and temperature. Our results reveal a generally enhanced scattering rate for higher magnetic fields, which is peaked at the magnetic field fulfilling the resonance condition. Furthermore, we find a slower phonon-induced relaxation at higher temperatures due to phonon occupation effects leading to a stronger increase of the scattering rates for phonon absorption in comparison to the phonon emission. [GRAPHICS] Sketch of the energetically lowest Landau levels with the Dirac cones for vanishing magnetic field in the background. The optical excitation with linear polarized light (yellow arrows) and the phonon-induced transitions (green arrows) are illustrated. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim