Towards chemical identification in atomic-resolution noncontact AFM imaging with silicon tips

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • University College London
  • Imperial College London

Abstract

In this study we use ab initio calculations and a pure silicon tip to study the tip-surface interaction with four characteristic insulating surfaces: (i) the narrow gap TiO2 (110) surface, (ii) the classic oxide MgO (001) surface, (iii) the ionic solid CaCO3 (101¯4) surface with molecular anion, and (iv) the wide gap CaF2 (111) surface. Generally we find that the tip-surface interaction strongly depends on the surface electronic structure due to the dominance of covalent bond formation with the silicon tip. However, we also find that in every case the strongest interaction is with the highest anion of the surface. This result suggests that, if the original silicon tip can be carefully controlled, it should be possible to immediately identify the species seen as bright in images of insulating surfaces. In order to provide a more complete picture we also compare these results to those for contaminated tips and suggest how applied voltage could also be used to probe chemical identity.

Details

Original languageEnglish
Article number195420
Pages (from-to)1-8
Number of pages8
JournalPhysical Review B
Volume68
Issue number19
Publication statusPublished - 2003
MoE publication typeA1 Journal article-refereed

ID: 3585907