Measurement of intrinsic dirac fermion cooling on the surface of the topological insulator Bi 2Se 3 using time-resolved and angle-resolved photoemission spectroscopy

Y. H. Wang, D. Hsieh, E. J. Sie, H. Steinberg, D. R. Gardner, Y. S. Lee, P. Jarillo-Herrero, N. Gedik*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

223 Scopus citations

Abstract

We perform time- and angle-resolved photoemission spectroscopy of a prototypical topological insulator (TI) Bi 2Se 3 to study the ultrafast dynamics of surface and bulk electrons after photoexcitation. By analyzing the evolution of surface states and bulk band spectra, we obtain their electronic temperature and chemical potential relaxation dynamics separately. These dynamics reveal strong phonon-assisted surface-bulk coupling at high lattice temperature and total suppression of inelastic scattering between the surface and the bulk at low lattice temperature. In this low temperature regime, the unique cooling of Dirac fermions in TI by acoustic phonons is manifested through a power law dependence of the surface temperature decay rate on carrier density.

Original languageAmerican English
Article number127401
JournalPhysical Review Letters
Volume109
Issue number12
DOIs
StatePublished - 20 Sep 2012
Externally publishedYes

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