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Tanuma Y, Kladnik G, Schio L, van Midden Mavrič M, Anézo B, Zupanič E, Bavdek G, Canton-Vitoria R, Floreano L, Tagmatarchis N, Wegner HA, Morgante A, Ewels CP, Cvetko D, Arčon D. Noncontact Layer Stabilization of Azafullerene Radicals: Route toward High-Spin-Density Surfaces. ACS Nano 2023; 17:25301-25310. [PMID: 38085812 PMCID: PMC10753892 DOI: 10.1021/acsnano.3c08717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/04/2023] [Accepted: 12/07/2023] [Indexed: 12/27/2023]
Abstract
We deposit azafullerene C59N• radicals in a vacuum on the Au(111) surface for layer thicknesses between 0.35 and 2.1 monolayers (ML). The layers are characterized using X-ray photoemission (XPS) and X-ray absorption fine structure (NEXAFS) spectroscopy, low-temperature scanning tunneling microscopy (STM), and by density functional calculations (DFT). The singly unoccupied C59N orbital (SUMO) has been identified in the N 1s NEXAFS/XPS spectra of C59N layers as a spectroscopic fingerprint of the molecular radical state. At low molecular coverages (up to 1 ML), films of monomeric C59N are stabilized with the nonbonded carbon orbital neighboring the nitrogen oriented toward the Au substrate, whereas in-plane intermolecular coupling into diamagnetic (C59N)2 dimers takes over toward the completion of the second layer. By following the C59N• SUMO peak intensity with increasing molecular coverage, we identify an intermediate high-spin-density phase between 1 and 2 ML, where uncoupled C59N• monomers in the second layer with pronounced radical character are formed. We argue that the C59N• radical stabilization of this supramonolayer phase of monomers is achieved by suppressed coupling to the substrate. This results from molecular isolation on top of the passivating azafullerene contact layer, which can be explored for molecular radical state stabilization and positioning on solid substrates.
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Affiliation(s)
- Yuri Tanuma
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Center
for Advanced Research of Energy and Materials (CAREM), Hokkaido University, Kita 13, Nishi 8, Kitaku, Sapporo 060-8628, Japan
| | - Gregor Kladnik
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | - Luca Schio
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | | | - Bastien Anézo
- Institut
des Matériaux de Nantes Jean Rouxel (IMN), UMR 6502 CNRS, Nantes University, 44322 Nantes, France
| | - Erik Zupanič
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Gregor Bavdek
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
- Faculty
of
Education, University of Ljubljana, Kardeljeva ploščad
16, SI-1000 Ljubljana Slovenia
| | - Ruben Canton-Vitoria
- Theoretical
and Physical Chemistry Institute, National
Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Luca Floreano
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | - Nikos Tagmatarchis
- Theoretical
and Physical Chemistry Institute, National
Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| | - Hermann A. Wegner
- Institute
of Organic Chemistry, Justus Liebig University
Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center
for Materials Research (ZfM/LaMa), Justus
Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Alberto Morgante
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
- Physics
Department, University of Trieste, Via Valerio 2, 34012 Trieste, Italy
| | - Christopher P. Ewels
- Institut
des Matériaux de Nantes Jean Rouxel (IMN), UMR 6502 CNRS, Nantes University, 44322 Nantes, France
| | - Dean Cvetko
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
- CNR-IOM, Istituto Officina dei Materiali, Basovizza Area Science Park, 34149 Trieste, Italy
| | - Denis Arčon
- Jožef
Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
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2
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Olivieri G, Kladnik G, Cvetko D, Brown MA. Determination of the valence band edge of Fe oxide nanoparticles dispersed in aqueous solution through resonant photoelectron spectroscopy from a liquid microjet. Nanoscale Adv 2021; 3:4513-4518. [PMID: 36133461 PMCID: PMC9419094 DOI: 10.1039/d1na00275a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/30/2021] [Indexed: 06/01/2023]
Abstract
We use X-ray photoemission and a near ambient pressure with a liquid microjet setup to investigate the electronic structure of FeOOH nanoparticles dispersed in aqueous solution. In particular, we show that by using X-ray resonant photoemission in dilute solutions, we can overcome the limits of conventional photoemission such as low nanoparticle-to-solvent signal ratio, and local nanoparticle charging and measure the valence band structure of FeOOH nanoparticles in aqueous solution with chemical specificity. The resonant photoemission signal across the Fe 2p3/2 absorption edge is measured for 2 wt% aqueous solutions of FeOOH nanoparticles (NPs) and the valence band maximum (VBM) of the hydrated FeOOH nanoparticles is determined. We compare the obtained VBM value in aqueous solution to that of FeOOH NPs in the dry phase. We show that the valence band edge position of NPs in the liquid phase can be accurately predicted from the values obtained in the dry phase provided that a simple potential shift due to solution chemistry is applied. Our results demonstrate the suitability of resonant photoemission in measuring the electronic structure of strongly diluted nanosystems where the conventional non-resonant photoemission technique fails.
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Affiliation(s)
- Giorgia Olivieri
- Laboratory for Surface Science and Technology, Department of Materials ETH Zürich, Vladimir-Prelog-Weg 5 CH-8093 Zürich Switzerland
| | - Gregor Kladnik
- Faculty for Mathematics and Physics, University of Ljubljana Jadranska 19 Ljubljana SI-1000 Slovenia
- IOM-CNR, Laboratorio TASC Basovizza SS-14, km 163.5 Trieste 34149 Italy
| | - Dean Cvetko
- Faculty for Mathematics and Physics, University of Ljubljana Jadranska 19 Ljubljana SI-1000 Slovenia
- IOM-CNR, Laboratorio TASC Basovizza SS-14, km 163.5 Trieste 34149 Italy
- Jožef Stefan Institute Jamova 39 Ljubljana SI-1000 Slovenia
| | - Matthew A Brown
- Laboratory for Surface Science and Technology, Department of Materials ETH Zürich, Vladimir-Prelog-Weg 5 CH-8093 Zürich Switzerland
- Metrology Research Centre, National Research Council of Canada Ottawa Ontario Canada
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3
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Doud EA, Starr RL, Kladnik G, Voevodin A, Montes E, Arasu NP, Zang Y, Zahl P, Morgante A, Venkataraman L, Vázquez H, Cvetko D, Roy X. Cyclopropenylidenes as Strong Carbene Anchoring Groups on Au Surfaces. J Am Chem Soc 2020; 142:19902-19906. [DOI: 10.1021/jacs.0c10743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Gregor Kladnik
- CNR-IOM Laboratorio Nazionale TASC, Basovizza
SS-14, km 163.5, 34149 Trieste, Italy
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
| | | | - Enrique Montes
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague 16200, Czech Republic
| | - Narendra P. Arasu
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague 16200, Czech Republic
| | | | - Percy Zahl
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Alberto Morgante
- CNR-IOM Laboratorio Nazionale TASC, Basovizza
SS-14, km 163.5, 34149 Trieste, Italy
- Department of Physics, University of Trieste, via A. Valerio 2, 34127 Trieste, Italy
| | | | - Héctor Vázquez
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague 16200, Czech Republic
| | - Dean Cvetko
- CNR-IOM Laboratorio Nazionale TASC, Basovizza
SS-14, km 163.5, 34149 Trieste, Italy
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
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4
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Low JZ, Kladnik G, Patera LL, Sokolov S, Lovat G, Kumarasamy E, Repp J, Campos LM, Cvetko D, Morgante A, Venkataraman L. The Environment-Dependent Behavior of the Blatter Radical at the Metal-Molecule Interface. Nano Lett 2019; 19:2543-2548. [PMID: 30884240 DOI: 10.1021/acs.nanolett.9b00275] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Stable organic radicals have potential applications for building organic spintronic devices. To fulfill this potential, the interface between organic radicals and metal electrodes must be well characterized. Here, through a combined effort that includes synthesis, scanning tunneling microscopy, X-ray spectroscopy, and single-molecule conductance measurements, we comprehensively probe the electronic interaction between gold metal electrodes and a benchtop stable radical-the Blatter radical. We find that despite its open-shell character and having a half-filled orbital close to the Fermi level, the radical is stable on a gold substrate under ultrahigh vacuum. We observe a Kondo resonance arising from the radical and spectroscopic signatures of its half-filled orbitals. By contrast, in solution-based single-molecule conductance measurements, the radical character is lost through oxidation with charge transfer occurring from the molecule to metal. Our experiments show that the stability of radical states can be very sensitive to the environment around the molecule.
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Affiliation(s)
- Jonathan Z Low
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Gregor Kladnik
- Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , SI-1000 Ljubljana , Slovenia
- CNR-IOM Laboratorio Nazionale TASC , Basovizza, SS-14, km 163.5 , I-34012 Trieste , Italy
| | - Laerte L Patera
- Institute of Experimental and Applied Physics , University of Regensburg , 93053 Regensburg , Germany
| | - Sophia Sokolov
- Institute of Experimental and Applied Physics , University of Regensburg , 93053 Regensburg , Germany
| | - Giacomo Lovat
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
| | - Elango Kumarasamy
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Jascha Repp
- Institute of Experimental and Applied Physics , University of Regensburg , 93053 Regensburg , Germany
| | - Luis M Campos
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
| | - Dean Cvetko
- Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , SI-1000 Ljubljana , Slovenia
- CNR-IOM Laboratorio Nazionale TASC , Basovizza, SS-14, km 163.5 , I-34012 Trieste , Italy
- J. Stefan Institute , Jamova 39 , SI-1000 Ljubljana , Slovenia
| | - Alberto Morgante
- CNR-IOM Laboratorio Nazionale TASC , Basovizza, SS-14, km 163.5 , I-34012 Trieste , Italy
- Department of Physics , University of Trieste , 34127 Trieste , Italy
| | - Latha Venkataraman
- Department of Chemistry , Columbia University , New York , New York 10027 , United States
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , United States
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5
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Lovat G, Doud EA, Lu D, Kladnik G, Inkpen MS, Steigerwald ML, Cvetko D, Hybertsen MS, Morgante A, Roy X, Venkataraman L. Determination of the structure and geometry of N-heterocyclic carbenes on Au(111) using high-resolution spectroscopy. Chem Sci 2019; 10:930-935. [PMID: 30774887 PMCID: PMC6346291 DOI: 10.1039/c8sc03502d] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [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: 08/07/2018] [Accepted: 11/04/2018] [Indexed: 12/01/2022] Open
Abstract
N-heterocyclic carbenes (NHCs) bind very strongly to transition metals due to their unique electronic structure featuring a divalent carbon atom with a lone pair in a highly directional sp2-hybridized orbital. As such, they can be assembled into monolayers on metal surfaces that have enhanced stability compared to their thiol-based counterparts. The utility of NHCs to form such robust self-assembled monolayers (SAMs) was only recently recognized and many fundamental questions remain. Here we investigate the structure and geometry of a series of NHCs on Au(111) using high-resolution X-ray photoelectron spectroscopy and density functional theory calculations. We find that the N-substituents on the NHC ring strongly affect the molecule-metal interaction and steer the orientation of molecules in the surface layer. In contrast to previous reports, our experimental and theoretical results provide unequivocal evidence that NHCs with N-methyl substituents bind to undercoordinated adatoms to form flat-lying complexes. In these SAMs, the donor-acceptor interaction between the NHC lone pair and the undercoordinated Au adatom is primarily responsible for the strong bonding of the molecules to the surface. NHCs with bulkier N-substituents prevent the formation of such complexes by forcing the molecules into an upright orientation. Our work provides unique insights into the bonding and geometry of NHC monolayers; more generally, it charts a clear path to manipulating the interaction between NHCs and metal surfaces using traditional coordination chemistry synthetic strategies.
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Affiliation(s)
- Giacomo Lovat
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , USA .
| | - Evan A Doud
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Deyu Lu
- Center for Functional Nanomaterials , Brookhaven National Laboratory , Upton , New York , USA
| | - Gregor Kladnik
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
- Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , Ljubljana , Slovenia
| | - Michael S Inkpen
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , USA .
| | | | - Dean Cvetko
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
- Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , Ljubljana , Slovenia
- J. Stefan Institute , Jamova 39 , Ljubljana , SI-1000 , Slovenia
| | - Mark S Hybertsen
- Center for Functional Nanomaterials , Brookhaven National Laboratory , Upton , New York , USA
| | - Alberto Morgante
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
- Department of Physics , University of Trieste , via A. Valerio 2 , 34127 , Trieste , Italy
| | - Xavier Roy
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics , Columbia University , New York , New York 10027 , USA .
- Department of Chemistry , Columbia University , New York , New York 10027 , USA .
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6
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Ravikumar A, Kladnik G, Müller M, Cossaro A, Bavdek G, Patera LL, Sánchez-Portal D, Venkataraman L, Morgante A, Brivio GP, Cvetko D, Fratesi G. Tuning ultrafast electron injection dynamics at organic-graphene/metal interfaces. Nanoscale 2018; 10:8014-8022. [PMID: 29667672 DOI: 10.1039/c7nr08737c] [Citation(s) in RCA: 2] [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: 06/08/2023]
Abstract
We compare the ultrafast charge transfer dynamics of molecules on epitaxial graphene and bilayer graphene grown on Ni(111) interfaces through first principles calculations and X-ray resonant photoemission spectroscopy. We use 4,4'-bipyridine as a prototypical molecule for these explorations as the energy level alignment of core-excited molecular orbitals allows ultrafast injection of electrons from a substrate to a molecule on a femtosecond timescale. We show that the ultrafast injection of electrons from the substrate to the molecule is ∼4 times slower on weakly coupled bilayer graphene than on epitaxial graphene. Through our experiments and calculations, we can attribute this to a difference in the density of states close to the Fermi level between graphene and bilayer graphene. We therefore show how graphene coupling with the substrate influences charge transfer dynamics between organic molecules and graphene interfaces.
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Affiliation(s)
- Abhilash Ravikumar
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125 Milano, Italy.
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7
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Olivieri G, Goel A, Kleibert A, Cvetko D, Brown MA. Quantitative ionization energies and work functions of aqueous solutions. Phys Chem Chem Phys 2018; 18:29506-29515. [PMID: 27747349 DOI: 10.1039/c6cp05682b] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Despite the ubiquitous nature of aqueous solutions across the chemical, biological and environmental sciences our experimental understanding of their electronic structure is rudimentary-qualitative at best. One of the most basic and seemingly straightforward properties of aqueous solutions-ionization energies-are (qualitatively) tabulated at the water-air interface for a mere handful of solutes, and the manner in which these results are obtained assume the aqueous solutions behave like a gas in the photoelectron experiment (where the vacuum levels of the aqueous solution and of the photoelectron analyzer are equilibrated). Here we report the experimental measure of a sizeable offset (ca. 0.6 eV) between the vacuum levels of an aqueous solution (0.05 M NaCl) and that of our photoelectron analyzer, indicating a breakdown of the gas-like vacuum level alignment assumption for the aqueous solution. By quantifying the vacuum level offset as a function of solution chemical composition our measurements enable, for the first time, quantitative determination of ionization energies in liquid solutions. These results reveal that the ionization energy of liquid water is not independent of the chemical composition of the solution as is usually inferred in the literature, a finding that has important ramifications as measured ionization energies are frequently used to validate theoretical models that posses the ability to provide microscopic insight not directly available by experiment. Finally, we derive the work function, or the electrochemical potential of the aqueous solution and show that it too varies with the chemical composition of the solution.
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Affiliation(s)
- Giorgia Olivieri
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Switzerland.
| | - Alok Goel
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Switzerland.
| | - Armin Kleibert
- Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland
| | - Dean Cvetko
- Faculty for Mathematics and Physics, University of Ljubljana and Jožef Stefan Institute, Ljubljana, Slovenia
| | - Matthew A Brown
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, Switzerland.
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8
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Toffoli D, Stredansky M, Feng Z, Balducci G, Furlan S, Stener M, Ustunel H, Cvetko D, Kladnik G, Morgante A, Verdini A, Dri C, Comelli G, Fronzoni G, Cossaro A. Electronic properties of the boroxine-gold interface: evidence of ultra-fast charge delocalization. Chem Sci 2017; 8:3789-3798. [PMID: 28580111 PMCID: PMC5436552 DOI: 10.1039/c6sc05632f] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [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: 12/22/2016] [Accepted: 03/07/2017] [Indexed: 12/30/2022] Open
Abstract
A combined theoretical and experimental study of the assembly of triphenylboroxines on Au(111) reveals the charge delocalization properties of the interface.
We performed a combined experimental and theoretical study of the assembly of phenylboronic acid on the Au(111) surface, which is found to lead to the formation of triphenylboroxines by spontaneous condensation of trimers of molecules. The interface between the boroxine group and the gold surface has been characterized in terms of its electronic properties, revealing the existence of an ultra-fast charge delocalization channel in the proximity of the oxygen atoms of the heterocyclic group. More specifically, the DFT calculations show the presence of an unoccupied electronic state localized on both the oxygen atoms of the adsorbed triphenylboroxine and the gold atoms of the topmost layer. By means of resonant Auger electron spectroscopy, we demonstrate that this interface state represents an ultra-fast charge delocalization channel. Boroxine groups are among the most widely adopted building blocks in the synthesis of covalent organic frameworks on surfaces. Our findings indicate that such systems, typically employed as templates for the growth of organic films, can also act as active interlayers that provide an efficient electronic transport channel bridging the inorganic substrate and organic overlayer.
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Affiliation(s)
- Daniele Toffoli
- Department of Chemical and Pharmaceutical Sciences , University of Trieste , via L. Giorgieri 1 , 34127 , Trieste , Italy .
| | - Matus Stredansky
- Department of Physics , University of Trieste , via A. Valerio 2 , 34127 , Trieste , Italy.,CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
| | - Zhijing Feng
- Department of Physics , University of Trieste , via A. Valerio 2 , 34127 , Trieste , Italy.,CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
| | - Gabriele Balducci
- Department of Chemical and Pharmaceutical Sciences , University of Trieste , via L. Giorgieri 1 , 34127 , Trieste , Italy .
| | - Sara Furlan
- Department of Chemical and Pharmaceutical Sciences , University of Trieste , via L. Giorgieri 1 , 34127 , Trieste , Italy .
| | - Mauro Stener
- Department of Chemical and Pharmaceutical Sciences , University of Trieste , via L. Giorgieri 1 , 34127 , Trieste , Italy .
| | - Hande Ustunel
- Department of Physics , Middle East Technical University , 06531 Ankara , Turkey
| | - Dean Cvetko
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy . .,Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , Ljubljana , Slovenia.,J. Stefan Institute , Jamova 39, SI-1000 , Ljubljana , Slovenia
| | - Gregor Kladnik
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy . .,Faculty of Mathematics and Physics , University of Ljubljana , Jadranska 19 , Ljubljana , Slovenia
| | - Alberto Morgante
- Department of Physics , University of Trieste , via A. Valerio 2 , 34127 , Trieste , Italy.,CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
| | - Alberto Verdini
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
| | - Carlo Dri
- Department of Physics , University of Trieste , via A. Valerio 2 , 34127 , Trieste , Italy.,CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
| | - Giovanni Comelli
- Department of Physics , University of Trieste , via A. Valerio 2 , 34127 , Trieste , Italy.,CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
| | - Giovanna Fronzoni
- Department of Chemical and Pharmaceutical Sciences , University of Trieste , via L. Giorgieri 1 , 34127 , Trieste , Italy .
| | - Albano Cossaro
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5 , 34012 Trieste , Italy .
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9
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Wardrip AG, Mazaheripour A, Hüsken N, Jocson J, Bartlett A, Lopez RC, Frey N, Markegard CB, Kladnik G, Cossaro A, Floreano L, Verdini A, Burke AM, Dickson MN, Kymissis I, Cvetko D, Morgante A, Sharifzadeh S, Nguyen HD, Gorodetsky AA. Length‐Independent Charge Transport in Chimeric Molecular Wires. Angew Chem Int Ed Engl 2016; 55:14267-14271. [DOI: 10.1002/anie.201605411] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/14/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Austin G. Wardrip
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Amir Mazaheripour
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Nina Hüsken
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Jonah‐Micah Jocson
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Andrew Bartlett
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Robert C. Lopez
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Nathan Frey
- Department of Electrical and Computer Engineering Boston University Boston MA 02215 USA
| | - Cade B. Markegard
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Gregor Kladnik
- CNR-IOM Laboratorio TASC Trieste 34149 Italy
- Faculty for Mathematics and Physics University of Ljubljana Jadranska 19 1000 Ljubljana Slovenia
| | | | | | | | - Anthony M. Burke
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Mary N. Dickson
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Ioannis Kymissis
- Department of Electrical Engineering Columbia University New York NY 10027 USA
| | - Dean Cvetko
- CNR-IOM Laboratorio TASC Trieste 34149 Italy
- Faculty for Mathematics and Physics University of Ljubljana Jadranska 19 1000 Ljubljana Slovenia
- Institut J. Stefan Jamova 39 1000 Ljubljana Slovenia
| | - Alberto Morgante
- CNR-IOM Laboratorio TASC Trieste 34149 Italy
- Department of Physics University of Trieste Trieste 34128 Italy
| | - Sahar Sharifzadeh
- Department of Electrical and Computer Engineering Boston University Boston MA 02215 USA
| | - Hung D. Nguyen
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Alon A. Gorodetsky
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
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10
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Wardrip AG, Mazaheripour A, Hüsken N, Jocson J, Bartlett A, Lopez RC, Frey N, Markegard CB, Kladnik G, Cossaro A, Floreano L, Verdini A, Burke AM, Dickson MN, Kymissis I, Cvetko D, Morgante A, Sharifzadeh S, Nguyen HD, Gorodetsky AA. Length‐Independent Charge Transport in Chimeric Molecular Wires. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201605411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Austin G. Wardrip
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Amir Mazaheripour
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Nina Hüsken
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Jonah‐Micah Jocson
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Andrew Bartlett
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Robert C. Lopez
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
| | - Nathan Frey
- Department of Electrical and Computer Engineering Boston University Boston MA 02215 USA
| | - Cade B. Markegard
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Gregor Kladnik
- CNR-IOM Laboratorio TASC Trieste 34149 Italy
- Faculty for Mathematics and Physics University of Ljubljana Jadranska 19 1000 Ljubljana Slovenia
| | | | | | | | - Anthony M. Burke
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Mary N. Dickson
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Ioannis Kymissis
- Department of Electrical Engineering Columbia University New York NY 10027 USA
| | - Dean Cvetko
- CNR-IOM Laboratorio TASC Trieste 34149 Italy
- Faculty for Mathematics and Physics University of Ljubljana Jadranska 19 1000 Ljubljana Slovenia
- Institut J. Stefan Jamova 39 1000 Ljubljana Slovenia
| | - Alberto Morgante
- CNR-IOM Laboratorio TASC Trieste 34149 Italy
- Department of Physics University of Trieste Trieste 34128 Italy
| | - Sahar Sharifzadeh
- Department of Electrical and Computer Engineering Boston University Boston MA 02215 USA
| | - Hung D. Nguyen
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
| | - Alon A. Gorodetsky
- Department of Chemistry University of California, Irvine Irvine CA 92697 USA
- Department of Chemical Engineering and Materials Science University of California, Irvine Irvine CA 92697 USA
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11
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Kladnik G, Puppin M, Coreno M, de Simone M, Floreano L, Verdini A, Morgante A, Cvetko D, Cossaro A. Ultrafast Charge Transfer Pathways Through A Prototype Amino-Carboxylic Molecular Junction. Nano Lett 2016; 16:1955-1959. [PMID: 26835843 DOI: 10.1021/acs.nanolett.5b05231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Charge transport properties of a vertically stacked organic heterojunction based on the amino-carboxylic (A-C) hydrogen bond coupling scheme are investigated by means of X-ray resonant photoemission and the core-hole clock method. We demonstrate that hydrogen bonding in molecular bilayers of benzoic acid/cysteamine (BA/CA) with an A-C coupling scheme opens a site selective pathway for ultrafast charge transport through the junction. Whereas charge transport from single BA layer directly coupled to the Au(111) is very fast and it is mediated by the phenyl group, the interposition of an anchoring layer of CA selectively hinders the delocalization of electrons from the BA phenyl group but opens a fast charge delocalization route through the BA orbitals close to the A-C bond. This evidences that hydrogen bonding established upon A-C recognition can be exploited to spatially/orbitally manipulate the charge transport properties of heteromolecular junctions.
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Affiliation(s)
- Gregor Kladnik
- Faculty of Mathematics and Physics, University of Ljubljana , Jadranska ul. 19, 1000 Ljubljana, Slovenia
| | - Michele Puppin
- Dipartimento di Fisica, Università di Trieste , via A. Valerio 2, I-34127 Trieste, Italy
- CNR-IOM Laboratorio TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Marcello Coreno
- CNR-ISM, UOS Trieste , Area Science Park Basovizza, 34149 Trieste, Italy
| | - Monica de Simone
- CNR-IOM Laboratorio TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Luca Floreano
- CNR-IOM Laboratorio TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Alberto Verdini
- CNR-IOM Laboratorio TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Alberto Morgante
- Dipartimento di Fisica, Università di Trieste , via A. Valerio 2, I-34127 Trieste, Italy
- CNR-IOM Laboratorio TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Dean Cvetko
- Faculty of Mathematics and Physics, University of Ljubljana , Jadranska ul. 19, 1000 Ljubljana, Slovenia
| | - Albano Cossaro
- CNR-IOM Laboratorio TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
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12
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Cvetko D, Fratesi G, Kladnik G, Cossaro A, Brivio GP, Venkataraman L, Morgante A. Ultrafast electron injection into photo-excited organic molecules. Phys Chem Chem Phys 2016; 18:22140-5. [DOI: 10.1039/c6cp04099c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
State-of-the-art X-ray spectroscopy allows femtosecond gating of energy levels of photo-excited molecules on a metal substrate enabling ultrafast and bi-directional charge transfer across the interface with controllable dependence on the molecular adsorption geometry.
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Affiliation(s)
- Dean Cvetko
- Faculty of Mathematics and Physics
- University of Ljubljana
- Slovenia
- CNR-IOM
- Laboratorio TASC
| | - Guido Fratesi
- ETSF and Dipartimento di Fisica
- Università degli Studi di Milano
- Italy
| | - Gregor Kladnik
- Faculty of Mathematics and Physics
- University of Ljubljana
- Slovenia
- CNR-IOM
- Laboratorio TASC
| | | | - Gian Paolo Brivio
- Dipartimento di Scienza dei Materiali
- Università di Milano-Bicocca
- Italy
| | - Latha Venkataraman
- Department of Applied Physics
- Columbia University
- New York
- USA
- Department of Chemistry
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13
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Adak O, Kladnik G, Bavdek G, Cossaro A, Morgante A, Cvetko D, Venkataraman L. Ultrafast Bidirectional Charge Transport and Electron Decoherence at Molecule/Surface Interfaces: A Comparison of Gold, Graphene, and Graphene Nanoribbon Surfaces. Nano Lett 2015; 15:8316-21. [PMID: 26574713 DOI: 10.1021/acs.nanolett.5b03962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We investigate bidirectional femtosecond charge transfer dynamics using the core-hole clock implementation of resonant photoemission spectroscopy from 4,4'-bipyridine molecular layers on three different surfaces: Au(111), epitaxial graphene on Ni(111), and graphene nanoribbons. We show that the lowest unoccupied molecular orbital (LUMO) of the molecule drops partially below the Fermi level upon core-hole creation in all systems, opening an additional decay channel for the core-hole, involving electron donation from substrate to the molecule. Furthermore, using the core-hole clock method, we find that the bidirectional charge transfer time between the substrate and the molecule is fastest on Au(111), with a 2 fs time, then around 4 fs for epitaxial graphene and slowest with graphene nanoribbon surface, taking around 10 fs. Finally, we provide evidence for fast phase decoherence of the core-excited LUMO* electron through an interaction with the substrate providing the first observation of such a fast bidirectional charge transfer across an organic/graphene interface.
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Affiliation(s)
- Olgun Adak
- Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States
| | - Gregor Kladnik
- Faculty of Mathematics and Physics, University of Ljubljana , Ljubljana, Slovenia
- Department of Physics, University of Trieste , Trieste, Italy
| | - Gregor Bavdek
- Faculty of Education, University of Ljubljana , Ljubljana, Slovenia
| | - Albano Cossaro
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Alberto Morgante
- Department of Physics, University of Trieste , Trieste, Italy
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Dean Cvetko
- Faculty of Mathematics and Physics, University of Ljubljana , Ljubljana, Slovenia
- CNR-IOM Laboratorio Nazionale TASC , Basovizza SS-14, km 163.5, I-34012 Trieste, Italy
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States
- Department of Chemistry, Columbia University , New York, New York 10027, United States
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14
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Batra A, Kladnik G, Gorjizadeh N, Meisner J, Steigerwald M, Nuckolls C, Quek SY, Cvetko D, Morgante A, Venkataraman L. Trimethyltin-Mediated Covalent Gold–Carbon Bond Formation. J Am Chem Soc 2014; 136:12556-9. [DOI: 10.1021/ja5061406] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Gregor Kladnik
- CNR-IOM Laboratorio Nazionale TASC, I-34012 Trieste, Italy
- Department
of Physics, University of Trieste, I-34127 Trieste, Italy
| | - Narjes Gorjizadeh
- Department of Physics, National University of Singapore, 117551 Singapore
- Institute of High
Performance Computing, Agency for Science, Technology and Research−A*STAR, 138632 Singapore
| | | | | | | | - Su Ying Quek
- Department of Physics, National University of Singapore, 117551 Singapore
- Institute of High
Performance Computing, Agency for Science, Technology and Research−A*STAR, 138632 Singapore
| | - Dean Cvetko
- Department
of Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia
- CNR-IOM Laboratorio Nazionale TASC, I-34012 Trieste, Italy
| | - Alberto Morgante
- CNR-IOM Laboratorio Nazionale TASC, I-34012 Trieste, Italy
- Department
of Physics, University of Trieste, I-34127 Trieste, Italy
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15
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Batra A, Cvetko D, Kladnik G, Adak O, Cardoso C, Ferretti A, Prezzi D, Molinari E, Morgante A, Venkataraman L. Probing the mechanism for graphene nanoribbon formation on gold surfaces through X-ray spectroscopy. Chem Sci 2014. [DOI: 10.1039/c4sc01584c] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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16
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Cossaro A, Cvetko D, Floreano L. Amino–carboxylic recognition on surfaces: from 2D to 2D + 1 nano-architectures. Phys Chem Chem Phys 2012; 14:13154-62. [DOI: 10.1039/c2cp41790a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Strojnik M, Omerzu A, Majkić A, Mihailovic PM, Lukan J, Bavdek G, Bratina G, Cvetko D, Topolovsek P, Mihailovic D. Ionization energy and energy gap structure of MoSI molecular wires: Kelvin probe, ultraviolet photoelectron spectroscopy, and cyclic voltammetry measurements. Langmuir 2011; 27:4296-4299. [PMID: 21413723 DOI: 10.1021/la1050767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The work function W of Mo(6)S(3)I(6) molecular nanowires is determined by Kelvin probe (KP) measurements, UV photoelectron spectroscopy (UPS), and cyclic voltammetry (CV). The values obtained by all three methods agree well, giving W = 4.8 ± 0.1 eV. CV measurements also give a gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of E(g) = 1.2 ± 0.1 eV, in agreement with recent optical measurements, but in disagreement with theoretical calculations, which predict the material to be a metal. The electronic structure of Mo(6)S(3)I(6) suggests use of the material in applications such as bulk heterostructure photovoltaics and transparent electrodes and for molecular electronics devices.
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18
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Locatelli A, Knox KR, Cvetko D, Menteş TO, Niño MA, Wang S, Yilmaz MB, Kim P, Osgood RM, Morgante A. Corrugation in exfoliated graphene: an electron microscopy and diffraction study. ACS Nano 2010; 4:4879-4889. [PMID: 20681631 DOI: 10.1021/nn101116n] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Low-energy electron microscopy and microprobe diffraction are used to image and characterize corrugation in SiO(2)-supported and suspended exfoliated graphene at nanometer length scales. Diffraction line-shape analysis reveals quantitative differences in surface roughness on length scales below 20 nm which depend on film thickness and interaction with the substrate. Corrugation decreases with increasing film thickness, reflecting the increased stiffness of multilayer films. Specifically, single-layer graphene shows a markedly larger short-range roughness than multilayer graphene. Due to the absence of interactions with the substrate, suspended graphene displays a smoother morphology and texture than supported graphene. A specific feature of suspended single-layer films is the dependence of corrugation on both adsorbate load and temperature, which is manifested by variations in the diffraction line shape. The effects of both intrinsic and extrinsic corrugation factors are discussed.
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Affiliation(s)
- Andrea Locatelli
- Elettra, Sincrotrone Trieste SCpA, 34149 Basovizza, Trieste, Italy.
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19
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Dell'Angela M, Kladnik G, Cossaro A, Verdini A, Kamenetska M, Tamblyn I, Quek SY, Neaton JB, Cvetko D, Morgante A, Venkataraman L. Relating energy level alignment and amine-linked single molecule junction conductance. Nano Lett 2010; 10:2470-2474. [PMID: 20578690 DOI: 10.1021/nl100817h] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Using photoemission spectroscopy, we determine the relationship between electronic energy level alignment at a metal-molecule interface and single-molecule junction transport data. We measure the position of the highest occupied molecular orbital (HOMO) relative to the Au metal Fermi level for three 1,4-benzenediamine derivatives on Au(111) and Au(110) with ultraviolet and resonant X-ray photoemission spectroscopy. We compare these results to scanning tunnelling microscope-based break-junction measurements of single molecule conductance and to first-principles calculations. We find that the energy difference between the HOMO and Fermi level for the three molecules adsorbed on Au(111) correlate well with changes in conductance and agree well with quasiparticle energies computed from first-principles calculations incorporating self-energy corrections. On the Au(110) that presents Au atoms with lower-coordination, critical in break-junction conductance measurements, we see that the HOMO level shifts further from the Fermi level. These results provide the first direct comparison of spectroscopic energy level alignment measurements with single molecule junction transport data.
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20
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Reichert J, Schiffrin A, Auwärter W, Weber-Bargioni A, Marschall M, Dell'angela M, Cvetko D, Bavdek G, Cossaro A, Morgante A, Barth JV. L-tyrosine on Ag(111): universality of the amino acid 2D zwitterionic bonding scheme? ACS Nano 2010; 4:1218-26. [PMID: 20092357 DOI: 10.1021/nn901669p] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We present a combined study of the adsorption and ordering of the l-tyrosine amino acid on the close-packed Ag(111) noble-metal surface in ultrahigh vacuum by means of low-temperature scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. On this substrate the biomolecules self-assemble at temperatures exceeding 320 K into linear structures primarily following specific crystallographic directions and evolve with larger molecular coverage into two-dimensional nanoribbons which are commensurate with the underlying atomic lattice. Our high resolution topographical STM data reveal noncovalent molecular dimerization within the highly ordered one-dimensional nanostructures, which recalls the geometrical pattern already seen in the l-methionine/Ag(111) system and supports a universal bonding scheme for amino acids on smooth and unreactive metal surfaces. The molecules desorb for temperatures above 350 K, indicating a relatively weak interaction between the molecules and the substrate. XPS measurements reveal a zwitterionic adsorption, whereas NEXAFS experiments show a tilted adsorption configuration of the phenol moiety. This enables the interdigitation between aromatic side chains of adjacent molecules via parallel-displaced pi-pi interactions which, together with the hydrogen-bonding capability of the hydroxyl functionality, presumably mediates the emergence of the self-assembled supramolecular nanoribbons.
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Affiliation(s)
- Joachim Reichert
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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21
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Abstract
We studied the molecular orientation of pentacene monolayer phases on the Au(110) surface by means of near-edge X-ray absorption spectroscopy at the carbon K-shell and scanning tunneling microscopy. The highest coverage phase, displaying a (6 x 8) symmetry, is found to be formed by two types of differently oriented molecules mimicking regular arrays of nanorails. Flat-lying molecules, aligned side-by-side with the long molecular axis along the [001] direction, form long crosstie chains extending in the [110] direction. In between the adjacent flat chains, additional molecules, tilted by 90 degrees around their molecular axis, line up head-to-tail into rails extending along [110]. These molecules are very weakly hybridized with the substrate, as indicated by their lowest unoccupied molecular orbitals, which closely resemble those of the free molecule. The nanorail structure is found to be stable up to 420 K in vacuum and to also remain in place after exposure to air, thus being a template well suited for further self-assembly of organic heterostructures. The tilted quasi-free molecules open the possibility for an optimal lateral pi-coupling to other molecules or molecular assemblies.
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Affiliation(s)
- Gregor Bavdek
- CNR-INFM Laboratorio Nazionale TASC, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy
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22
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Schiffrin A, Riemann A, Auwärter W, Pennec Y, Weber-Bargioni A, Cvetko D, Cossaro A, Morgante A, Barth JV. Zwitterionic self-assembly of L-methionine nanogratings on the Ag(111) surface. Proc Natl Acad Sci U S A 2007; 104:5279-84. [PMID: 17372212 PMCID: PMC1838441 DOI: 10.1073/pnas.0607867104] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Indexed: 11/18/2022] Open
Abstract
The engineering of complex architectures from functional molecules on surfaces provides new pathways to control matter at the nanoscale. In this article, we present a combined study addressing the self-assembly of the amino acid L-methionine on Ag(111). Scanning tunneling microscopy data reveal spontaneous ordering in extended molecular chains oriented along high-symmetry substrate directions. At intermediate coverages, regular biomolecular gratings evolve whose periodicity can be tuned at the nanometer scale by varying the methionine surface concentration. Their characteristics and stability were confirmed by helium atomic scattering. X-ray photoemission spectroscopy and high-resolution scanning tunneling microscopy data reveal that the L-methionine chaining is mediated by zwitterionic coupling, accounting for both lateral links and molecular dimerization. This methionine molecular recognition scheme is reminiscent of sheet structures in amino acid crystals and was corroborated by molecular mechanics calculations. Our findings suggest that zwitterionic assembly of amino acids represents a general construction motif to achieve biomolecular nanoarchitectures on surfaces.
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Affiliation(s)
- Agustin Schiffrin
- *Departments of Chemistry and of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Andreas Riemann
- *Departments of Chemistry and of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Department of Physics and Astronomy, Western Washington University, Bellingham, WA 98225
| | - Willi Auwärter
- *Departments of Chemistry and of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Yan Pennec
- *Departments of Chemistry and of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Alex Weber-Bargioni
- *Departments of Chemistry and of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Dean Cvetko
- Department of Physics, University of Ljubljana, SI-1001 Ljubljana, Slovenia
- Laboratorio Istituto Nazionale per la Fisica della Material/Tecnologie Avanzate e Nanoscienza (INFM/TASC), 34012 Trieste, Italy; and
| | - Albano Cossaro
- Laboratorio Istituto Nazionale per la Fisica della Material/Tecnologie Avanzate e Nanoscienza (INFM/TASC), 34012 Trieste, Italy; and
| | - Alberto Morgante
- Laboratorio Istituto Nazionale per la Fisica della Material/Tecnologie Avanzate e Nanoscienza (INFM/TASC), 34012 Trieste, Italy; and
- Dipartimento di Fisica, Università di Trieste, 34127 Trieste, Italy
| | - Johannes V. Barth
- *Departments of Chemistry and of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
- Physik Department E20, Technische Universität München, D-85478 Garching, Germany
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23
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Cossaro A, Terreni S, Cavalleri O, Prato M, Cvetko D, Morgante A, Floreano L, Canepa M. Electronic and geometric characterization of the L-cysteine paired-row phase on Au(110). Langmuir 2006; 22:11193-8. [PMID: 17154602 DOI: 10.1021/la061833r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We have studied the vapor-phase deposition of L-cysteine on the Au(110) surface by means of synchrotron-based techniques. Relying on a comparison with previous X-ray photoemission analysis, we have assigned the fine structure of the C K-shell X-ray absorption spectra to the nonequivalent carbon bonds within the molecule. In particular, the C1s --> sigma* transition, where the sigma* state is mainly localized on the C-S bond, is shifted well below the ionization threshold, at approximately -5 eV from the characteristic pi* transition line related to carboxylic group. From the polarization dependence of the absorption spectra in the monolayer coverage range, the molecules are found to lay flat on the surface with both the C-S bond and the carboxylic group almost parallel to the surface. We performed in situ complementary surface X-ray diffraction, SXRD, measurements to probe the rearrangement of the Au atoms beneath the L-cysteine molecules. Since the early stage of deposition, L-cysteine domains are formed which display an intermediate fourfold symmetry along [001]. The self-assembly of molecules into paired rows, extending along the [1(-)10] direction, is fully compatible with our observations, as has been reported for the case of D-cysteine molecules grown on Au(110) [Kühnle, A. et al. Phys. Rev. Lett. 2004, 93, 086101.]
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Affiliation(s)
- Albano Cossaro
- CNR-INFM Laboratorio Nazionale TASC, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy
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24
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Abstract
We studied the growth of pentacene (C22H14) on the Au(110) surface by means of He atom scattering and Synchrotron X-ray photoemission. We found that two-dimensional commensurate growth only occurs in the monolayer range for a substrate temperature, T(s), higher than approximately 370 K. Larger amounts of deposited molecules forms three-dimensional uncorrelated clusters on the wetting layer. The desorption of second layer molecules occurs at T(s) > or = 420 K. The highest coverage ordered phase displays a (6 x 8) symmetry and corresponds to the saturation coverage at T(s) = 420 K. The (3 x 6) symmetry phase, recently reported for a multilayer planar film [Ph. Guaino, et al. Appl. Phys. Lett. 2004, 85, 2777], is only found at a coverage slightly lower than the (6 x 8) one. The (3 x 6) phase corresponds to the saturation coverage of the first layer at T(s) = 470 K.
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Affiliation(s)
- Luca Floreano
- CNR-INFM Laboratorio Nazionale TASC, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy.
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25
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Gonella G, Terreni S, Cvetko D, Cossaro A, Mattera L, Cavalleri O, Rolandi R, Morgante A, Floreano L, Canepa M. Ultrahigh Vacuum Deposition of l-Cysteine on Au(110) Studied by High-Resolution X-ray Photoemission: From Early Stages of Adsorption to Molecular Organization. J Phys Chem B 2005; 109:18003-9. [PMID: 16853311 DOI: 10.1021/jp051549t] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report on a high-resolution X-ray photoemission spectroscopy study on molecular-thick layers of L-cysteine deposited under ultrahigh vacuum conditions on Au(110). The analysis of core level shifts allowed us to distinguish unambiguously the states of the first-layer molecules from those of molecules belonging to the second layer. The first-layer molecules strongly interact with the metal through their sulfur headgroup. The multipeaked structure of the N 1s, O 1s, and C 1s core levels is interpreted in terms of different molecular moieties. The neutral acidic fraction (HSCH2CH(NH2)COOH) is abundant at low coverage likely associated with isolated molecules or dimers. The zwitterionic phase (HSCH2CH(NH3+)COO-) is largely dominant as the coverage approaches the monolayer limit and is related to the formation of ordered self-assembled molecular structures indicated by electron diffraction patterns. The occurrence of a small amount of cationic molecules (HSCH2CH(NH3+)COOH) is also discussed. The second-layer molecules mainly display zwitterionic character and are weakly adsorbed. Mild annealing up to 100 degrees C leads to the desorption of the second-layer molecules leaving electronic states of the first layer unaltered.
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Affiliation(s)
- Grazia Gonella
- Dipartimento di Fisica, Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
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Cossaro A, Cvetko D, Bavdek G, Floreano L, Gotter R, Morgante A, Evangelista F, Ruocco A. Copper−Phthalocyanine Induced Reconstruction of Au(110). J Phys Chem B 2004. [DOI: 10.1021/jp049108h] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. Cossaro
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - D. Cvetko
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - G. Bavdek
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - L. Floreano
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - R. Gotter
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - A. Morgante
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - F. Evangelista
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
| | - A. Ruocco
- Laboratorio TASC dell'Istituto Nazionale per la Fisica della Materia, Basovizza SS-14, Km 163.5, I-34012 Trieste, Italy, Department of Physics, University of Ljubljana, Ljubljana, Slovenia, Jožef Stefan Institute, Ljubljana, Slovenia, Department of Physics, University of Trieste, Trieste, Italy, INFM unit of Roma Tre and Physics Department, University of Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy
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Wider J, Baumberger F, Sambi M, Gotter R, Verdini A, Bruno F, Cvetko D, Morgante A, Greber T, Osterwalder J. Atomically resolved images from near node photoelectron holography experiments on Al(111). Phys Rev Lett 2001; 86:2337-2340. [PMID: 11289923 DOI: 10.1103/physrevlett.86.2337] [Citation(s) in RCA: 6] [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] [Received: 09/15/2000] [Indexed: 05/23/2023]
Abstract
Szöke's concept for electron holography is hampered by forward scattering that dominates electron diffraction from electron point sources below the surface top layer. Forward scattering was proposed to be suppressed if the anisotropic nature of the electron source wave is exploited [T. Greber and J. Osterwalder, Chem. Phys. Lett. 256, 653 (1996)]. Experiments show a strong suppression of forward scattering in Al(111) if Al 2s photoelectrons (E(kin) = 952 eV) are measured near the nodal plane of the outgoing p wave. The holographic reconstruction from such diffraction data provides three dimensional images of atomic sites in unit cells with a size of more than 10 A.
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Affiliation(s)
- J Wider
- Physik Institut der Universität Zürich, Switzerland
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Prato S, Floreano L, Cvetko D, Renzi VD, Morgante A, Modesti S, Biscarini F, Zamboni R, Taliani C. Anisotropic Ordered Planar Growth of α-Sexithienyl Thin Films. J Phys Chem B 1999. [DOI: 10.1021/jp9905878] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nardelli MB, Cvetko D, Floreano L, Gotter R, Morgante A, Peloi M, Tommasini F, Danieli R, Rossini S, Taliani C, Zamboni R. Ordering of a prototypical conjugated molecular system during monolayer growth on the (1 x 2)-Au(110) surface. Phys Rev B Condens Matter 1996; 53:1095-1098. [PMID: 9983564 DOI: 10.1103/physrevb.53.1095] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cvetko D, Floreano L, Morgante A, Peloi M, Tommasini F. Low-energy vibrations at the InSb(110) surface. Phys Rev B Condens Matter 1995; 52:16720-16726. [PMID: 9981075 DOI: 10.1103/physrevb.52.16720] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cvetko D, Floreano L, Morgante A, Peloi M, Tommasini F, Cháb V, Prince KC. Terrace distribution during sputtering and recovery of InSb(110) studied by He-atom scattering. Phys Rev B Condens Matter 1995; 52:14941-14946. [PMID: 9980835 DOI: 10.1103/physrevb.52.14941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cvetko D, Floreano L, Morgante A, Peloi M, Tommasini F, Cháb V, Prince KC. Vacancy island nucleation and inverse growth of InSb(110). Phys Rev B Condens Matter 1995; 51:17957-17964. [PMID: 9978831 DOI: 10.1103/physrevb.51.17957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cvetko D, Floreano L, Lausi A, Morgante A, Peloi M, Tommasini F, Kirsten E, Rieder KH. Electron density of (1 x 2)Pt(110) from He reflectivity measurements. Phys Rev B Condens Matter 1995; 51:11055-11060. [PMID: 9977811 DOI: 10.1103/physrevb.51.11055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cortona P, Dondi MG, Cvetko D, Lausi A, Morgante A, Prince KC, Tommasini F. Electron density and structure of the (1 x 2)-Au(110) surface studied by He-beam scattering. Phys Rev B Condens Matter 1993; 47:6705-6710. [PMID: 10004642 DOI: 10.1103/physrevb.47.6705] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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