Direct determination of mode-projected electron-phonon coupling in the time domain

Ultrafast spectroscopies have become an important tool for elucidating the microscopic description and dynamical properties of quantum materials. In particular, by tracking the dynamics of nonthermal electrons, a material’s dominant scattering processes can be revealed. Here, we present a method for extracting the electron-phonon coupling strength in the time domain, using time- and angle-resolved photoemission spectroscopy (TR-ARPES). This method is demonstrated in graphite, where we investigate the dynamics of photoinjected electrons at the$K¯$point, detecting quantized energy-loss processes that correspond to the emission of strongly coupled optical phonons. We show that the observed characteristic time scale for spectral weight transfer mediated by phonon-scattering processes allows for the direct quantitative extraction of electron-phonon matrix elements for specific modes.

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Award ID(s):
Publication Date:
NSF-PAR ID:
10126474
Journal Name:
Science
Volume:
366
Issue:
6470
Page Range or eLocation-ID:
p. 1231-1236
ISSN:
0036-8075
Publisher:
American Association for the Advancement of Science (AAAS)
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