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Sweetman A, Lekkas I, Moriarty P. Mechano-chemical manipulation of Sn chains on Si(1 0 0) by NC-AFM. J Phys Condens Matter 2017; 29:074003. [PMID: 28035086 DOI: 10.1088/1361-648x/29/7/074003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We investigate the atomic structure of Sn dimer chains grown on the Si(1 0 0) surface using non-contact atomic force microscopy (NC-AFM) at cryogenic temperatures. We find that similar to the native Si(1 0 0) dimer structure, the ground state of the Sn dimer structure is buckled at low temperature. At 5 K we show that the buckling state of the Sn dimers may be controllably, and reversibly, manipulated with atomic precision by close approach of the tip, without modification of the underlying substrate buckling structure. At intermediate cryogenic temperatures we observe changes in the configuration of the dimer chains in the region where the tip-sample interaction is very weak, suggesting that the energy barrier to transit between configurations is sufficiently small to be surmounted at 78 K.
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Jarvis SP, Sweetman AM, Lekkas I, Champness NR, Kantorovich L, Moriarty P. Simulated structure and imaging of NTCDI on Si(1 1 1)-7 × 7 : a combined STM, NC-AFM and DFT study. J Phys Condens Matter 2015; 27:054004. [PMID: 25414147 DOI: 10.1088/0953-8984/27/5/054004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The adsorption of naphthalene tetracarboxylic diimide (NTCDI) on Si(1 1 1)-7 × 7 is investigated through a combination of scanning tunnelling microscopy (STM), noncontact atomic force microscopy (NC-AFM) and density functional theory (DFT) calculations. We show that NTCDI adopts multiple planar adsorption geometries on the Si(1 1 1)-7 × 7 surface which can be imaged with intramolecular bond resolution using NC-AFM. DFT calculations reveal adsorption is dominated by covalent bond formation between the molecular oxygen atoms and the surface silicon adatoms. The chemisorption of the molecule is found to induce subtle distortions to the molecular structure, which are observed in NC-AFM images.
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Affiliation(s)
- S P Jarvis
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
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Sweetman AM, Jarvis SP, Sang H, Lekkas I, Rahe P, Wang Y, Wang J, Champness N, Kantorovich L, Moriarty P. Mapping the force field of a hydrogen-bonded assembly. Nat Commun 2014; 5:3931. [PMID: 24875276 PMCID: PMC4050271 DOI: 10.1038/ncomms4931] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/22/2014] [Indexed: 02/03/2023] Open
Abstract
Hydrogen bonding underpins the properties of a vast array of systems spanning a wide variety of scientific fields. From the elegance of base pair interactions in DNA to the symmetry of extended supramolecular assemblies, hydrogen bonds play an essential role in directing intermolecular forces. Yet fundamental aspects of the hydrogen bond continue to be vigorously debated. Here we use dynamic force microscopy (DFM) to quantitatively map the tip-sample force field for naphthalene tetracarboxylic diimide molecules hydrogen-bonded in two-dimensional assemblies. A comparison of experimental images and force spectra with their simulated counterparts shows that intermolecular contrast arises from repulsive tip-sample interactions whose interpretation can be aided via an examination of charge density depletion across the molecular system. Interpreting DFM images of hydrogen-bonded systems therefore necessitates detailed consideration of the coupled tip-molecule system: analyses based on intermolecular charge density in the absence of the tip fail to capture the essential physical chemistry underpinning the imaging mechanism.
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Affiliation(s)
- A. M. Sweetman
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
- These authors contributed equally to this work
| | - S. P. Jarvis
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
- These authors contributed equally to this work
| | - Hongqian Sang
- School of Physics and Technology, Centre for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, China
- Department of Physics, King’s College London, The Strand, London WC2R 2LS, UK
- These authors contributed equally to this work
| | - I. Lekkas
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - P. Rahe
- Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112-0830, USA
| | - Yu Wang
- School of Physics and Technology, Centre for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, China
| | - Jianbo Wang
- School of Physics and Technology, Centre for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, China
| | - N.R. Champness
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - L. Kantorovich
- Department of Physics, King’s College London, The Strand, London WC2R 2LS, UK
| | - P. Moriarty
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
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