Intervalley scattering by acoustic phonons in two-dimensional MoS2 revealed by double-resonance Raman spectroscopy

Bruno R. Carvalho, Yuanxi Wang, Sandro Mignuzzi, Debdulal Roy, Mauricio Terrones, Cristiano Fantini, Vincent H. Crespi, Leandro M. Malard, Marcos A. Pimenta

Research output: Contribution to journalArticle

91 Scopus citations

Abstract

Double-resonance Raman scattering is a sensitive probe to study the electron-phonon scattering pathways in crystals. For semiconducting two-dimensional transition-metal dichalcogenides, the double-resonance Raman process involves different valleys and phonons in the Brillouin zone, and it has not yet been fully understood. Here we present a multiple energy excitation Raman study in conjunction with density functional theory calculations that unveil the double-resonance Raman scattering process in monolayer and bulk MoS2. Results show that the frequency of some Raman features shifts when changing the excitation energy, and first-principle simulations confirm that such bands arise from distinct acoustic phonons, connecting different valley states. The double-resonance Raman process is affected by the indirect-to-direct bandgap transition, and a comparison of results in monolayer and bulk allows the assignment of each Raman feature near the M or K points of the Brillouin zone. Our work highlights the underlying physics of intervalley scattering of electrons by acoustic phonons, which is essential for valley depolarization in MoS2.

Original languageEnglish (US)
Article number14670
JournalNature communications
Volume8
DOIs
StatePublished - Mar 9 2017

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Intervalley scattering by acoustic phonons in two-dimensional MoS<sub>2</sub> revealed by double-resonance Raman spectroscopy'. Together they form a unique fingerprint.

  • Cite this