Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction

Yannick Gillet, Stefan Kontur, Matteo Giantomassi, Claudia Draxl, Xavier Gonze

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Raman spectra obtained by the inelastic scattering of light by crystalline solids contain contributions from first-order vibrational processes (e.g. the emission or absorption of one phonon, a quantum of vibration) as well as higher-order processes with at least two phonons being involved. At second order, coupling with the entire phonon spectrum induces a response that may strongly depend on the excitation energy, and reflects complex processes more difficult to interpret. In particular, excitons (i.e. bound electron-hole pairs) may enhance the absorption and emission of light, and couple strongly with phonons in resonance conditions. We design and implement a first-principles methodology to compute second-order Raman scattering, incorporating dielectric responses and phonon eigenstates obtained from density-functional theory and many-body theory. We demonstrate our approach for the case of silicon, relating frequency-dependent relative Raman intensities, that are in excellent agreement with experiment, to different vibrations and regions of the Brillouin zone. We show that exciton-phonon coupling, computed from first principles, indeed strongly affects the spectrum in resonance conditions. The ability to analyze second-order Raman spectra thus provides direct insight into this interaction.

Original languageEnglish
Article number7344
JournalScientific Reports
Volume7
Issue number1
DOIs
Publication statusPublished - 1 Dec 2017
Externally publishedYes

Fingerprint

Dive into the research topics of 'Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction'. Together they form a unique fingerprint.

Cite this