Journal article

Damping of the collective amplitude mode in superconductors with strong electron-phonon coupling

  • Murakami, Yuta Department of Physics, University of Fribourg, Switzerland
  • Werner, Philipp Department of Physics, University of Fribourg, Switzerland
  • Tsuji, Naoto RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
  • Aoki, Hideo Department of Physics, University of Tokyo, Hongo, Tokyo, Japan - Electronics and Photonics Research Institute, Advanced Industrial Science and Technology (AIST), Umezono, Tsukuba, Ibaraki, Japan
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Published in:
  • Physical Review B. - 2016, vol. 94, no. 11, p. 115126
English We study the effect of strong electron-phonon interactions on the damping of the Higgs amplitude mode in superconductors by means of nonequilibrium dynamical mean-field simulations of the Holstein model. In contrast to the BCS dynamics, we find that the damping of the Higgs mode strongly depends on the temperature, becoming faster as the system approaches the transition temperature. The damping at low temperatures is well described by a power law, while near the transition temperature the damping shows exponential-like behavior. We explain this crossover in terms of a temperature- dependent quasiparticle lifetime caused by the strong electron-phonon coupling, which smears the superconducting gap edge and makes the relaxation of the Higgs mode into quasiparticles more efficient at elevated temperatures. We also reveal that the phonon dynamics can soften the Higgs mode, which results in a slower damping.
Faculté des sciences et de médecine
Département de Physique
  • English
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