Mechanisms of electron-phonon coupling unraveled in momentum and time: The case of soft-phonons in TiSe$_2$
| Autor: | Otto, Martin R., Pöhls, Jan-Hendrik, de Cotret, Laurent P. René, Stern, Mark J., Sutton, Mark, Siwick, Bradley J. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Science Advances Vol. 7, no. 20, 2021 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1126/sciadv.abf2810 |
| Popis: | The complex coupling between charge carriers and phonons is responsible for diverse phenomena in condensed matter. We apply ultrafast electron diffuse scattering to unravel electron-phonon coupling phenomena in 1T-TiSe$_2$ in both momentum and time. We are able to distinguish effects due to the real part of the many-body bare electronic susceptibility, $\Re\left[\chi_0(\mathbf{q})\right]$, from those due to the electron-phonon coupling vertex, $g_{\mathbf{q}}$, by following the response of semi-metallic (normal phase) 1T-TiSe$_2$ to the selective photo-doping of carriers into the electron pocket at the Fermi level. Quasi-impulsive and wavevector-specific renormalization of soft zone-boundary phonon frequencies (stiffening) is observed, followed by wavevector-independent electron-phonon equilibration. These results unravel the underlying mechanisms driving the phonon softening that is associated with the charge density wave transition at lower temperatures. Comment: 14 pages including appendices and references |
| Databáze: | arXiv |
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