Imaging point defects in a liquid environment: A model AFM study

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Effects of the liquid on atomic force microscopy (AFM) imaging are examined for a model system consisting of a hexagonal flake of seven Lennard-Jones (LJ) atoms as a multiatom tip, a monolayer of LJ crystal containing a single point defect as a substrate, and three-site model water as the liquid. A previous simulation [Koutsos et al., Europhys. Lett. 26, 103 (1994)] has shown that the true atomic resolution of a point defect cannot be achieved in vacuum by use of the multiatom tip. Here we examine the feasibility of such atomic resolution when both the tip and substrate are immersed in a liquid. The liquid-induced interaction between the tip and the substrate is evaluated in the framework of the integral equation theory of molecular fluids extended for the system consisting of an infinitely large crystal. It is found that the potential of mean force indeed manifests the point defect even when the tip and the substrate are a few Angstroms apart. This implies that in the liquid environment the point defect could be discerned in the constant-height mode of AFM measurement. For the constant-load mode of AFM, a characteristic potential can be used to determine the stable, metastable, and unstable vertical position (height) of the tip at any lateral position. The contour surface of the stable heights reveals periodic features of the underlying lattice of the substrate except in the vicinity of the defect, provided certain load is applied.

Original languageEnglish
Pages (from-to)14328-14333
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume60
Issue number20
Publication statusPublished - 1999
Externally publishedYes

Fingerprint

Point defects
point defects
Atomic force microscopy
atomic force microscopy
Imaging techniques
Liquids
Substrates
liquids
Crystals
flakes
Integral equations
Monolayers
crystals
integral equations
Vacuum
Atoms
Defects
Fluids
Water
vacuum

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Imaging point defects in a liquid environment : A model AFM study. / Koga, Kenichiro.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 60, No. 20, 1999, p. 14328-14333.

Research output: Contribution to journalArticle

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