Ultrafast Surface Carrier Dynamics in the Topological Insulator Bi2Te3

Abstract : We discuss the ultrafast evolution of the surface electronic structure of the topological insulator Bi2Te3 following a femtosecond laser excitation. Using time and angle-resolved photoelectron spectroscopy, we provide a direct real-time visualization of the transient carrier population of both the surface states and the bulk conduction band. We find that the thermalization of the surface states is initially determined by interband scattering from the bulk conduction band, lasting for about 0.5 ps; subsequently, few picoseconds are necessary for the Dirac cone non-equilibrium electrons to recover a Fermi-Dirac distribution, while their relaxation extends over more than 10 ps. The surface sensitivity of our measurements makes it possible to estimate the range of the bulk-surface interband scattering channel, indicating that the process is effective over a distance of 5 nm or less. This establishes a correlation between the nanoscale thickness of the bulk charge reservoir and the evolution of the ultrafast carrier dynamics in the surface Dirac cone.
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Article dans une revue
Nano Letters, American Chemical Society, 2012, 12 (7), pp.3532-3536. 〈10.1021/nl301035x〉
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https://hal-polytechnique.archives-ouvertes.fr/hal-01068621
Contributeur : Gaëlle Bruant <>
Soumis le : vendredi 26 septembre 2014 - 09:14:42
Dernière modification le : jeudi 10 mai 2018 - 01:58:08

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Mahdi Hajlaoui, E. Papalazarou, J. Mauchain, G. Lantz, N. Moisan, et al.. Ultrafast Surface Carrier Dynamics in the Topological Insulator Bi2Te3. Nano Letters, American Chemical Society, 2012, 12 (7), pp.3532-3536. 〈10.1021/nl301035x〉. 〈hal-01068621〉

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