Abstract
Photoemission and phonon spectroscopies have yielded widely varying estimates of the electron-phonon coupling parameter on the surfaces of topological insulators, even for a particular material and technique. We connect the results of these experiments by determining the Dirac fermion quasiparticle spectral function using information from measured spectra of a strongly interacting, low-lying optical surface phonon band. The manifest spectral features resulting from the coupling are found to vary on energy scales 1 meV and are distinct from those traditionally observed in the case of acoustic phonons in metals. We explore different means of determining from the electron perspective and identify definitions that yield values consistent with phonon spectroscopy.
- Received 22 October 2013
- Revised 6 February 2014
DOI:https://doi.org/10.1103/PhysRevB.89.075425
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