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Ultrafast nonequilibrium carrier dynamics in a single graphene layer


M. Breusing, S. Kuehn, T. Winzer, E. Malic, F. Milde, N. Severin, J.P. Rabe, C. Ropers, A. Knorr, and T. Elsaesser

Phys. Rev. B 83 (2011) 153410 , ( DOI:10.1103/PhysRevB.83.153410 ) ;


Abstract: Nonequilibrium carrier dynamics in single exfoliated graphene layers on muscovite substrates is studied by ultrafast optical pump-probe spectroscopy and compared with microscopic theory. The very high 10-fs time resolution allows for mapping carrier equilibration into a quasi-Fermi distribution within the first 250 fs and the subsequent slower relaxation stages. Coulomb-mediated carrier-carrier and carrier-optical phonon scattering are essential for forming hot separate Fermi distributions of electrons and holes which cool by intraband optical phonon emission. Carrier cooling and recombination are influenced by hot phonon effects.