Hot carrier relaxation of Dirac fermions in bilayer epitaxial graphene
| Autor: | Huang, J., Alexander-Webber, J. A., Janssen, T. J. B. M., Tzalenchuk, A., Yager, T., Lara-Avila, S., Kubatkin, S., Myers-Ward, R. L., Wheeler, V. D., Gaskill, D. K., Nicholas, R. J. |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | J. Phys.: Condens. Matter 27 164202 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/0953-8984/27/16/164202 |
| Popis: | Energy relaxation of hot Dirac fermions in bilayer epitaxial graphene is experimentally investigated by magnetotransport measurements on Shubnikov-de Haas oscillations and weak localization. The hot-electron energy loss rate is found to follow the predicted Bloch-Gr\"uneisen power-law behaviour of $T^4$ at carrier temperatures from 1.4 K up to $\sim$100 K, due to electron-acoustic phonon interactions with a deformation potential coupling constant of 22 eV. A carrier density dependence $n_e^{-1.5}$ in the scaling of the $T^4$ power law is observed in bilayer graphene, in contrast to the $n_e^{-0.5}$ dependence in monolayer graphene, leading to a crossover in the energy loss rate as a function of carrier density between these two systems. The electron-phonon relaxation time in bilayer graphene is also shown to be strongly carrier density dependent, while it remains constant for a wide range of carrier densities in monolayer graphene. Our results and comparisons between the bilayer and monolayer exhibit a more comprehensive picture of hot carrier dynamics in graphene systems. Comment: 9 pages, 8 figures |
| Databáze: | arXiv |
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