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Excitonic effects on Raman, infrared absorption spectroscopy, and coherent phonon from ab initio time-dependent aGW approach

ORAL

Abstract

The interplay between electron-phonon couplings and electron-hole correlation effects in electron dynamics is fundamentally interesting and relevant for applications ranging from energy harvesting to quantum information sciences. We extend the time-dependent adiabatic GW (TD-aGW) theory to include electron-phonon (e-ph) couplings with a classical phonon approximation. Based on a perturbative expansion of electron-phonon and electron-light (e-l) couplings, we derive the infrared (IR) absorption and Raman scattering spectra with excitonic effects. We show that excitonic effects can be included by dressing the proper e-ph or e-l vertices with electron-hole ladder diagrams, which are readily available from standard GW-Bethe-Salpeter equation calculations. We demonstrate that the exciton-phonon coupling strength and exciton energy landscape can be accessed by analyzing resonance Raman spectrum. We further explore coherent phonon signatures in time-resolved angle-resolved photoemission spectroscopy for a monolayer MoS2 by conducting real-time simulations with the developed approach.

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Presenters

  • Yang-hao Chan

    Academia Sinica

Authors

  • Yang-hao Chan

    Academia Sinica

  • Steven G Louie

    University of California, Berkeley, University of California, Berkeley and Lawrence Berkeley National Lab, University of California, Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley, Berkeley, CA, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA

  • Zhenglu Li

    University of Southern California, Unviersity of Southern California, Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA