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Measurement of Intrinsic Dirac Fermion Cooling on the Surface of the Topological Insulator Bi2Se3 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, and N. Gedik
Phys. Rev. Lett. 109, 127401 – Published 20 September 2012
Physics logo See Synopsis: Electrons that Take the Heat
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Abstract

We perform time- and angle-resolved photoemission spectroscopy of a prototypical topological insulator (TI) Bi2Se3 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.

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  • Received 11 April 2012

DOI:https://doi.org/10.1103/PhysRevLett.109.127401

© 2012 American Physical Society

Synopsis

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Electrons that Take the Heat

Published 20 September 2012

An ultra-high-speed camera has captured the cooling of surface electrons in topological insulators.

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Authors & Affiliations

Y. H. Wang1,2, D. Hsieh1, E. J. Sie1, H. Steinberg1, D. R. Gardner1, Y. S. Lee1, P. Jarillo-Herrero1, and N. Gedik1,*

  • 1Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
  • 2Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA

  • *To whom all correspondence should be addressed. gedik@mit.edu

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Vol. 109, Iss. 12 — 21 September 2012

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