Two-phonon relaxation processes of the graphene in the magnetic field

We theoretically investigate the electron relaxation mediated by two-phonon (LO+LA) scattering between Landau levels in graphene. We chose the transitions from LL n=1 to n=0 and from n=2 to n = − 1 as examples to study the temperature and magnetic field dependence of two-phonon relaxation processes. We find that the relaxation time is very fast and is in the nanoseconds scale. Moreover, the temperature dependence of the relaxation rates is very different depending on the lattice relaxation strength. We hope that our results can be confirmed by many related experiments.