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Preis T, Vrbica S, Eroms J, Repp J, van Ruitenbeek JM. Current-Induced One-Dimensional Diffusion of Co Adatoms on Graphene Nanoribbons. NANO LETTERS 2021; 21:8794-8799. [PMID: 34652923 PMCID: PMC8554795 DOI: 10.1021/acs.nanolett.1c03073] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/24/2021] [Indexed: 06/13/2023]
Abstract
One-dimensional diffusion of Co adatoms on graphene nanoribbons has been induced and investigated by means of scanning tunnelling microscopy (STM). To this end, the nanoribbons and the Co adatoms have been imaged before and after injecting current pulses into the nanoribbons, with the STM tip in direct contact with the ribbon. We observe current-induced motion of the Co atoms along the nanoribbons, which is approximately described by a distribution expected for a thermally activated one-dimensional random walk. This indicates that the nanoribbons reach temperatures far beyond 100 K, which is well above the temperature of the underlying Au substrate. This model system can be developed further for the study of electromigration at the single-atom level.
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Affiliation(s)
- Tobias Preis
- Institute
of Experimental and Applied Physics, University
of Regensburg, 93040 Regensburg, Germany
| | - Sasha Vrbica
- Huygens-Kamerlingh
Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands
| | - Jonathan Eroms
- Institute
of Experimental and Applied Physics, University
of Regensburg, 93040 Regensburg, Germany
| | - Jascha Repp
- Institute
of Experimental and Applied Physics, University
of Regensburg, 93040 Regensburg, Germany
| | - Jan M. van Ruitenbeek
- Huygens-Kamerlingh
Onnes Laboratory, Leiden University, 2333 CA Leiden, The Netherlands
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Kammert JD, Chemburkar A, Miyake N, Neurock M, Davis RJ. Reaction Kinetics and Mechanism for the Catalytic Reduction of Propionic Acid over Supported ReO x Promoted by Pd. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04328] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- James D. Kammert
- Department of Chemical Engineering, University of Virginia, 102 Engineer’s Way, P.O. Box 400741, Charlottesville, Virginia 22904-4741, United States
| | - Ashwin Chemburkar
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue Southeast, Minneapolis, Minnesota 55455-0132, United States
| | - Naomi Miyake
- Department of Chemical Engineering, University of Virginia, 102 Engineer’s Way, P.O. Box 400741, Charlottesville, Virginia 22904-4741, United States
| | - Matthew Neurock
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue Southeast, Minneapolis, Minnesota 55455-0132, United States
| | - Robert J. Davis
- Department of Chemical Engineering, University of Virginia, 102 Engineer’s Way, P.O. Box 400741, Charlottesville, Virginia 22904-4741, United States
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Blanco-Rey M, Tremblay JC. Diffusion of hydrogen interstitials in the near-surface region of Pd(111) under the influence of surface coverage and external static electric fields. J Chem Phys 2015; 142:154704. [PMID: 25903902 DOI: 10.1063/1.4917537] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Past scanning tunneling microscopy (STM) experiments of H manipulation on Pd(111), at low temperature, have shown that it is possible to induce diffusion of surface species as well as of those deeply buried under the surface. Several questions remain open regarding the role of subsurface site occupancies. In the present work, the interaction potential of H atoms with Pd(111) under various H coverage conditions is determined by means of density functional theory calculations in order to provide an answer to two of these questions: (i) whether subsurface sites are the final locations for the H impurities that attempt to emerge from bulk regions, and (ii) whether penetration of the surface is a competing route of on-surface diffusion during depletion of surface H on densely covered Pd(111). We find that a high H coverage has the effect of blocking resurfacing of H atoms travelling from below, which would otherwise reach the surface fcc sites, but it hardly alters deeper diffusion energy barriers. Penetration is unlikely and restricted to high occupancies of hcp hollows. In agreement with experiments, the Pd lattice expands vertically as a consequence of H atoms being blocked at subsurface sites, and surface H enhances this expansion. STM tip effects are included in the calculations self-consistently as an external static electric field. The main contribution to the induced surface electric dipoles originates from the Pd substrate polarisability. We find that the electric field has a non-negligible effect on the H-Pd potential in the vicinity of the topmost Pd atomic layer, yet typical STM intensities of 1-2 VÅ(-1) are insufficient to invert the stabilities of the surface and subsurface equilibrium sites.
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Affiliation(s)
- M Blanco-Rey
- Departamento de Física de Materiales, Facultad de Químicas UPV/EHU, Apartado 1072, 20018 Donostia-San Sebastián, Spain
| | - J C Tremblay
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 3, D-14195 Berlin, Germany
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Ju SP, Weng MH, Huang WC. Potential applications of two ultrathin Pd nanowires to the hydrogen economy. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm33696k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Baber AE, Tierney HL, Lawton TJ, Sykes ECH. An Atomic-Scale View of Palladium Alloys and their Ability to Dissociate Molecular Hydrogen. ChemCatChem 2010. [DOI: 10.1002/cctc.201000309] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Blake MM, Nanayakkara SU, Claridge SA, Fernández-Torres LC, Sykes ECH, Weiss PS. Identifying Reactive Intermediates in the Ullmann Coupling Reaction by Scanning Tunneling Microscopy and Spectroscopy. J Phys Chem A 2009; 113:13167-72. [DOI: 10.1021/jp903590c] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Meaghan M. Blake
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300
| | - Sanjini U. Nanayakkara
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300
| | - Shelley A. Claridge
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300
| | - Luis C. Fernández-Torres
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300
| | - E. Charles H. Sykes
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300
| | - Paul S. Weiss
- Departments of Chemistry and Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300
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Ternes M, Heinrich AJ, Schneider WD. Spectroscopic manifestations of the Kondo effect on single adatoms. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:053001. [PMID: 21817287 DOI: 10.1088/0953-8984/21/5/053001] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The present topical review focuses on recent advances concerning an intriguing phenomenon in condensed matter physics, the scattering of conduction electrons at the localized spin of a magnetic impurity: the Kondo effect. Spectroscopic signatures of this effect have been observed in the past by high-resolution photoemission which, however, has the drawback of averaging over a typical surface area of 1 mm(2). By combining the atomic-scale spatial resolution of the scanning tunneling microscope (STM) with an energy resolution of a few tens of µeV achievable nowadays in scanning tunneling spectroscopy (STS), and by exposing the magnetic adatom to external magnetic fields, our understanding of the interaction of a single magnetic impurity with the conduction electrons of the nonmagnetic host has been considerably deepened. New insight has emerged by taking advantage of quantum size effects in the metallic support and by decoupling the magnetic adatom from the supporting host metal, for instance by embedding it inside a molecule or by separating it by an ultrathin insulating film from the metal surface. In this way, Kondo resonances and Kondo temperatures can be tailored and manipulated by changing the local density of states of the environment. In the weak coupling limit between a Kondo impurity and a superconductor only a convolution of tip and sample DOS is observed while for strongly coupled systems midgap states appear, indicating superconducting pair breaking. Magnetic impurities with co-adsorbed hydrogen on metallic surfaces show pseudo-Kondo resonances owing to very low-energy vibrational excitations detected by inelastic tunneling spectroscopy. One of the most recent achievements in the field has been the clarification of the role of magnetic anisotropy in the Kondo effect for localized spin systems with a spin larger than S = 1/2.
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Affiliation(s)
- Markus Ternes
- IBM Almaden Research Center, 650 Harry Road, San Jose, CA, USA. Institut de Physique des Nanostructures, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Moore AM, Weiss PS. Functional and spectroscopic measurements with scanning tunneling microscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2008; 1:857-882. [PMID: 20636100 DOI: 10.1146/annurev.anchem.1.031207.112932] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Invented as a surface analytical technique capable of imaging individual atoms and molecules in real space, scanning tunneling microscopy (STM) has developed and advanced into a technique able to measure a variety of structural, functional, and spectroscopic properties and relationships at the single-molecule level. Here, we review basic STM operation and image interpretation, techniques developed to manipulate single atoms and molecules with the STM to measure functional properties of surfaces, local spectroscopies used to characterize atoms and molecules at the single-molecule level, and surface perturbations affecting surface coverage and surface reactions. Each section focuses on determining the identity and function of chemical species so as to elucidate information beyond topography with STM.
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Affiliation(s)
- Amanda M Moore
- Department of Chemistry, Pennsylvania State University, University Park, 16802, USA
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Pivetta M, Ternes M, Patthey F, Schneider WD. Diatomic molecular switches to enable the observation of very-low-energy vibrations. PHYSICAL REVIEW LETTERS 2007; 99:126104. [PMID: 17930525 DOI: 10.1103/physrevlett.99.126104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Indexed: 05/25/2023]
Abstract
Using low-temperature scanning tunneling microscopy and spectroscopy, we found that the coadsorption of atomic hydrogen to single transition-metal and rare-earth-metal atoms on a Ag(100) surface gives rise to surprising phenomena, a bias dependent switching from a large to a small apparent size of the diatomic molecules and a concomitant appearance of very low-energy vibrational features of 3 to 7 meV in the differential conductance spectra. These phenomena, which have until now escaped observation, may be of general relevance for low-temperature adsorption.
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Affiliation(s)
- Marina Pivetta
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Institut de Physique des Nanostructures, CH-1015 Lausanne, Switzerland
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