Exfoliation of natural van der Waals heterostructures to a single unit cell thickness

Research output: Contribution to journalArticle

  • External authors:
  • Peter Toth
  • Alexander Rakowski
  • Aidan Rooney
  • Aleksey Kozikov
  • Colin Woods
  • Jun Yin
  • Viktor Zolyomi
  • Thanasis Georgiou
  • Konstantin Novoselov

Abstract

Weak interlayer interactions in van der Waals crystals facilitate their mechanical exfoliation to monolayer and few-layer two-dimensional materials, which often exhibit striking physical phenomena absent in their bulk form. Here we utilize mechanical exfoliation to produce a two-dimensional form of a mineral franckeite and show that the phase segregation of chemical species into discrete layers at the sub-nanometre scale facilitates franckeite’s layered structure and basal cleavage down to a single unit cell thickness. This behaviour is likely to be common in a wider family of complex minerals and could be exploited for a single-step synthesis of van der Waals heterostructures, as an alternative to artificial stacking of individual two-dimensional crystals. We demonstrate p-type electrical conductivity and remarkable electrochemical properties of the exfoliated crystals, showing promise for a range of applications, and use the density functional theory calculations of franckeite’s electronic band structure to rationalize the experimental results.

Bibliographical metadata

Original languageEnglish
Pages (from-to)14410
Number of pages11
JournalNature communications
Volume8
DOIs
StatePublished - 13 Feb 2017