Hot carrier cooling by acoustic phonons in epitaxial graphene by ultrafast pump-probe spectroscopy



We report the application nondegenerate ultrafast mid-infrared spectroscopy to investigate the acoustic phonon cooling process in epitaxial graphene. We show that the power-dependent experimental results match theoretical predictions of the low temperature acoustic cooling process. The hot phonon effect in acoustic phonon cooling is observed experimentally, and a deformation potential of 30 eV can be determined from fitting the data. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)