eprintid: 1433814 rev_number: 27 eprint_status: archive userid: 608 dir: disk0/01/43/38/14 datestamp: 2014-07-04 19:01:13 lastmod: 2021-10-04 01:37:38 status_changed: 2014-07-04 19:01:13 type: article metadata_visibility: show item_issues_count: 0 creators_name: Gao, DZ creators_name: Grenz, J creators_name: Watkins, MB creators_name: Canova, FF creators_name: Schwarz, A creators_name: Wiesendanger, R creators_name: Shluger, AL title: Using Metallic Noncontact Atomic Force Microscope Tips for Imaging Insulators and Polar Molecules: Tip Characterization and Imaging Mechanisms ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F60 keywords: NC-AFM, insulator, imaging mechanism, metallic tip, virtual AFM note: © 2014 American Chemical Society. Terms of Use CC-BY. PubMed ID: 24787716 abstract: We demonstrate that using metallic tips for noncontact atomic force microscopy (NC-AFM) imaging at relatively large (>0.5 nm) tip–surface separations provides a reliable method for studying molecules on insulating surfaces with chemical resolution and greatly reduces the complexity of interpreting experimental data. The experimental NC-AFM imaging and theoretical simulations were carried out for the NiO(001) surface as well as adsorbed CO and Co-Salen molecules using Cr-coated Si tips. The experimental results and density functional theory calculations confirm that metallic tips possess a permanent electric dipole moment with its positive end oriented toward the sample. By analyzing the experimental data, we could directly determine the dipole moment of the Cr-coated tip. A model representing the metallic tip as a point dipole is described and shown to produce NC-AFM images of individual CO molecules adsorbed onto NiO(001) in good quantitative agreement with experimental results. Finally, we discuss methods for characterizing the structure of metal-coated tips and the application of these tips to imaging dipoles of large adsorbed molecules. date: 2014-05 official_url: http://dx.doi.org/10.1021/nn501785q oa_status: green full_text_type: pub primo: open primo_central: open_green verified: verified_manual elements_source: WoS-Lite elements_id: 960217 doi: 10.1021/nn501785q lyricists_name: Shluger, Alexander lyricists_name: Watkins, Matthew lyricists_id: ASHLU39 lyricists_id: MWATK35 full_text_status: public publication: ACS NANO volume: 8 number: 5 pagerange: 5339 - 5351 issn: 1936-0851 citation: Gao, DZ; Grenz, J; Watkins, MB; Canova, FF; Schwarz, A; Wiesendanger, R; Shluger, AL; (2014) Using Metallic Noncontact Atomic Force Microscope Tips for Imaging Insulators and Polar Molecules: Tip Characterization and Imaging Mechanisms. ACS NANO , 8 (5) 5339 - 5351. 10.1021/nn501785q <https://doi.org/10.1021/nn501785q>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1433814/1/nn501785q.pdf