Electronic Origin of Optically-Induced Sub-Picosecond Lattice Dynamics in MoSe2 Monolayer

Lindsay Bassman, Aravind Krishnamoorthy, Hiroyuki Kumazoe, Masaaki Misawa, Fuyuki Shimojo, Rajiv K. Kalia, Aiichiro Nakano, Priya Vashishta

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Atomically thin layers of transition metal dichalcogenide (TMDC) semiconductors exhibit outstanding electronic and optical properties, with numerous applications such as valleytronics. While unusually rapid and efficient transfer of photoexcitation energy to atomic vibrations was found in recent experiments, its electronic origin remains unknown. Here, we study the lattice dynamics induced by electronic excitation in a model TMDC monolayer, MoSe2, using nonadiabatic quantum molecular dynamics simulations. Simulation results show sub-picosecond disordering of the lattice upon photoexcitation, as measured by the Debye-Waller factor, as well as increasing disorder for higher densities of photogenerated electron-hole pairs. Detailed analysis shows that the rapid, photoinduced lattice dynamics are due to phonon-mode softening, which in turn arises from electronic Fermi surface nesting. Such mechanistic understanding can help guide optical control of material properties for functionalizing TMDC layers, enabling emerging applications such as phase change memories and neuromorphic computing.

Original languageEnglish
Pages (from-to)4653-4658
Number of pages6
JournalNano Letters
Volume18
Issue number8
DOIs
Publication statusPublished - Aug 8 2018
Externally publishedYes

Keywords

  • 2D materials
  • MoSe
  • TMDC
  • electronic structure
  • nonadiabatic quantum molecular dynamics
  • structural dynamics

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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