Resonance-Enhanced Excitation of Interlayer Vibrations in Atomically Thin Black Phosphorus

Nannan Mao, Yuxuan Lin, Ya Qing Bie, Tomás Palacios, Liangbo Liang, Riichiro Saito, Xi Ling, Jing Kong, William A. Tisdale

Research output: Contribution to journalArticlepeer-review

Abstract

The strength of interlayer coupling critically affects the physical properties of 2D materials such as black phosphorus (BP), where the electronic structure depends sensitively on layer thickness. Rigid-layer vibrations reflect directly the interlayer coupling strength in 2D van der Waals solids, but measurement of these characteristic frequencies is made difficult by sample instability and small Raman scattering cross sections in atomically thin elemental crystals. Here, we overcome these challenges in BP by performing resonance-enhanced low-frequency Raman scattering under an argon-protective environment. Interlayer breathing modes for atomically thin BP were previously unobservable under conventional (nonresonant) excitation but became strongly enhanced when the excitation energy matched the sub-band electronic transitions of few-layer BP, down to bilayer thicknesses. The measured out-of-plane interlayer force constant was found to be 10.1 × 1019 N/m3 in BP, which is comparable to graphene. Accurate characterization of the interlayer coupling strength lays the foundation for future exploration of BP twisted structures and heterostructures.

Original languageEnglish
Pages (from-to)4809-4815
Number of pages7
JournalNano Letters
Volume21
Issue number11
DOIs
Publication statusPublished - 2021 Jun 9

Keywords

  • black phosphorus
  • interband electronic transitions
  • interlayer interaction
  • resonance Raman scattering
  • rigid-layer lattice vibrations

ASJC Scopus subject areas

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

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