1
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Su S, Zhao J, Ly TH. Scanning Probe Microscopies for Characterizations of 2D Materials. SMALL METHODS 2024:e2400211. [PMID: 38766949 DOI: 10.1002/smtd.202400211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/12/2024] [Indexed: 05/22/2024]
Abstract
2D materials are intriguing due to their remarkably thin and flat structure. This unique configuration allows the majority of their constituent atoms to be accessible on the surface, facilitating easier electron tunneling while generating weak surface forces. To decipher the subtle signals inherent in these materials, the application of techniques that offer atomic resolution (horizontal) and sub-Angstrom (z-height vertical) sensitivity is crucial. Scanning probe microscopy (SPM) emerges as the quintessential tool in this regard, owing to its atomic-level spatial precision, ability to detect unitary charges, responsiveness to pico-newton-scale forces, and capability to discern pico-ampere currents. Furthermore, the versatility of SPM to operate under varying environmental conditions, such as different temperatures and in the presence of various gases or liquids, opens up the possibility of studying the stability and reactivity of 2D materials in situ. The characteristic flatness, surface accessibility, ultra-thinness, and weak signal strengths of 2D materials align perfectly with the capabilities of SPM technologies, enabling researchers to uncover the nuanced behaviors and properties of these advanced materials at the nanoscale and even the atomic scale.
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Affiliation(s)
- Shaoqiang Su
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, 999077, China
| | - Jiong Zhao
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, 999077, P. R. China
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, 518057, China
| | - Thuc Hue Ly
- Department of Chemistry and Center of Super-Diamond & Advanced Films (COSDAF), City University of Hong Kong, Kowloon, 999077, China
- Department of Chemistry and State Key Laboratory of Marine Pollution, City University of Hong Kong, Hong Kong, 999077, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
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2
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Rothe K, Néel N, Kröger J. Unveiling the nature of atomic defects in graphene on a metal surface. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2024; 15:416-425. [PMID: 38655541 PMCID: PMC11035987 DOI: 10.3762/bjnano.15.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 03/18/2024] [Indexed: 04/26/2024]
Abstract
Low-energy argon ion bombardment of graphene on Ir(111) induces atomic-scale defects at the surface. Using a scanning tunneling microscope, the two smallest defects appear as a depression without discernible interior structure suggesting the presence of vacancy sites in the graphene lattice. With an atomic force microscope, however, only one kind can be identified as a vacancy defect with four missing carbon atoms, while the other kind reveals an intact graphene sheet. Spatially resolved spectroscopy of the differential conductance and the measurement of total-force variations as a function of the lateral and vertical probe-defect distance corroborate the different character of the defects. The tendency of the vacancy defect to form a chemical bond with the microscope probe is reflected by the strongest attraction at the vacancy center as well as by hysteresis effects in force traces recorded for tip approach to and retraction from the Pauli repulsion range of vertical distances.
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Affiliation(s)
- Karl Rothe
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Nicolas Néel
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
| | - Jörg Kröger
- Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany
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3
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Ukraintsev E, Rezek B. Non-contact non-resonant atomic force microscopy method for measurements of highly mobile molecules and nanoparticles. Ultramicroscopy 2023; 253:113816. [PMID: 37531754 DOI: 10.1016/j.ultramic.2023.113816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/13/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023]
Abstract
Atomic force microscopy (AFM) is nowadays indispensable versatile scanning probe method widely employed for fundamental and applied research in physics, chemistry, biology as well as industrial metrology. Conventional AFM systems can operate in various environments such as ultra-high vacuum, electrolyte solutions, or controlled gas atmosphere. Measurements in ambient air are prevalent due to their technical simplicity; however, there are drawbacks such as formation of water meniscus that greatly increases attractive interaction (adhesion) between the tip and the sample, reduced spatial resolution, and too strong interactions leading to tip and/or sample modifications. Here we show how the attractive forces in AFM under ambient conditions can be used with advantage to probe surface properties in a very sensitive way even on highly mobile molecules and nanoparticles. We introduce a stable non-contact non-resonant (NCNR) AFM method which enables to reliably perform measurements in the attractive force regime even in air by controlling the tip position in the intimate surface vicinity without touching it. We demonstrate proof-of-concept results on helicene-based macrocycles, DNA on mica, and nanodiamonds on SiO2. We compare the results with other conventional AFM regimes, showing NCNR advantages such as higher spatial resolution, reduced tip contamination, and negligible sample modification. We analyze principle physical and chemical mechanisms influencing the measurements, discuss issues of stability and various possible method implementations. We explain how the NCNR method can be applied in any AFM system by a mere software modification. The method thus opens a new research field for measurements of highly sensitive and mobile nanoscale objects under air and other environments.
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Affiliation(s)
- Egor Ukraintsev
- Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6, 166 27, Czech Republic.
| | - Bohuslav Rezek
- Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6, 166 27, Czech Republic
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4
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Freeney SE, Slot MR, Gardenier TS, Swart I, Vanmaekelbergh D. Electronic Quantum Materials Simulated with Artificial Model Lattices. ACS NANOSCIENCE AU 2022; 2:198-224. [PMID: 35726276 PMCID: PMC9204828 DOI: 10.1021/acsnanoscienceau.1c00054] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 11/29/2022]
Abstract
![]()
The
band structure and electronic properties of a material are
defined by the sort of elements, the atomic registry in the crystal,
the dimensions, the presence of spin–orbit coupling, and the
electronic interactions. In natural crystals, the interplay of these
factors is difficult to unravel, since it is usually not possible
to vary one of these factors in an independent way, keeping the others
constant. In other words, a complete understanding of complex electronic
materials remains challenging to date. The geometry of two- and one-dimensional
crystals can be mimicked in artificial lattices. Moreover, geometries
that do not exist in nature can be created for the sake of further
insight. Such engineered artificial lattices can be better controlled
and fine-tuned than natural crystals. This makes it easier to vary
the lattice geometry, dimensions, spin–orbit coupling, and
interactions independently from each other. Thus, engineering and
characterization of artificial lattices can provide unique insights.
In this Review, we focus on artificial lattices that are built atom-by-atom
on atomically flat metals, using atomic manipulation in a scanning
tunneling microscope. Cryogenic scanning tunneling microscopy allows
for consecutive creation, microscopic characterization, and band-structure
analysis by tunneling spectroscopy, amounting in the analogue quantum
simulation of a given lattice type. We first review the physical elements
of this method. We then discuss the creation and characterization
of artificial atoms and molecules. For the lattices, we review works
on honeycomb and Lieb lattices and lattices that result in crystalline
topological insulators, such as the Kekulé and “breathing”
kagome lattice. Geometric but nonperiodic structures such as electronic
quasi-crystals and fractals are discussed as well. Finally, we consider
the option to transfer the knowledge gained back to real materials,
engineered by geometric patterning of semiconductor quantum wells.
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Affiliation(s)
- Saoirsé E. Freeney
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Marlou R. Slot
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Thomas S. Gardenier
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Ingmar Swart
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Daniel Vanmaekelbergh
- Condensed Matter and Interfaces, Debye Institute of Nanomaterial Science, University of Utrecht, Princetonplein 5, 3584 CC Utrecht, The Netherlands
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5
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Fan D, Chelikowsky JR. Atomic Fingerprinting of Heteroatoms Using Noncontact Atomic Force Microscopy. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2102977. [PMID: 34596948 DOI: 10.1002/smll.202102977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Immense strides have been made in increasing the resolution of scanning probe microscopy. Noncontact atomic force microscopy (nc-AFM) now offers one the ability to characterize and visualize single molecules with subatomic resolution. Specifically, nc-AFM with a carbon monoxide (CO) functionalized tip has the ability to discriminate functional groups (-CC-, -CH2 , -CO, …), although discriminating atomic species often remains as an ongoing challenge. Here, real-space pseudopotentials constructed within density functional theory are employed to accurately simulate nc-AFM images of molecules containing heteroatoms (S, I, and N) within dibenzothiophene (DBT), 2-iodotriphenylene (ITP), acridine (ACR) and ferrous phthalocyanine (FePc). It is found that S and I atoms can be easily identified from C based on their unique features. For N atoms, a use of tip functionalization is proposed to effectively discriminate them from C atoms.
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Affiliation(s)
- Dingxin Fan
- McKetta Department of Chemical Engineering, The University of Texas at Austin, POB 4.302, 201 East 24th St. C0200, Austin, TX, 78712, USA
| | - James R Chelikowsky
- McKetta Department of Chemical Engineering, Department of Physics, Center for Computational Materials, Oden Institute for Computational Engineering and Sciences, The University of Texas at Austin, POB 4.324, 201 East 24th St. C0200, Austin, TX, 78712, USA
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6
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Creating a regular array of metal-complexing molecules on an insulator surface at room temperature. Nat Commun 2020; 11:6424. [PMID: 33349635 PMCID: PMC7752910 DOI: 10.1038/s41467-020-20189-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 11/11/2020] [Indexed: 11/08/2022] Open
Abstract
Controlling self-assembled nanostructures on bulk insulators at room temperature is crucial towards the fabrication of future molecular devices, e.g., in the field of nanoelectronics, catalysis and sensor applications. However, at temperatures realistic for operation anchoring individual molecules on electrically insulating support surfaces remains a big challenge. Here, we present the formation of an ordered array of single anchored molecules, dimolybdenum tetraacetate, on the (10.4) plane of calcite (CaCO3). Based on our combined study of atomic force microscopy measurements and density functional theory calculations, we show that the molecules neither diffuse nor rotate at room temperature. The strong anchoring is explained by electrostatic interaction of an ideally size-matched molecule. Especially at high coverage, a hard-sphere repulsion of the molecules and the confinement at the calcite surface drives the molecules to form locally ordered arrays, which is conceptually different from attractive linkers as used in metal-organic frameworks. Our work demonstrates that tailoring the molecule-surface interaction opens up the possibility for anchoring individual metal-complexing molecules into ordered arrays.
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7
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Liebig A, Hapala P, Weymouth AJ, Giessibl FJ. Quantifying the evolution of atomic interaction of a complex surface with a functionalized atomic force microscopy tip. Sci Rep 2020; 10:14104. [PMID: 32839507 PMCID: PMC7445177 DOI: 10.1038/s41598-020-71077-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/07/2020] [Indexed: 11/09/2022] Open
Abstract
Terminating the tip of an atomic force microscope with a CO molecule allows data to be acquired with a well-known and inert apex. Previous studies have shown conflicting results regarding the electrostatic interaction, indicating in some cases that the negative charge at the apex of the CO dominates, whereas in other cases the positive charge at the end of the metal tip dominates. To clarify this, we investigated [Formula: see text](111). [Formula: see text] is an ionic crystal and the (111) surface does not possess charge inversion symmetry. Far from the surface, the interaction is dominated by electrostatics via the negative charge at the apex. Closer to the surface, Pauli repulsion and CO bending dominate, which leads to an unexpected appearance of the complex 3-atom unit cell. We compare simulated data in which the electrostatics are modeled by point particles versus a charge density calculated by DFT. We also compare modeling Pauli repulsion via individual Lennard-Jones potentials versus a total charge density overlap. In doing so, we determine forcefield parameters useful for future investigations of biochemical processes.
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Affiliation(s)
- Alexander Liebig
- Institute of Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany.
| | - Prokop Hapala
- Department of Applied Physics, Aalto University, Aalto, Finland.,Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague 6, Czech Republic
| | - Alfred J Weymouth
- Institute of Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany
| | - Franz J Giessibl
- Institute of Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany.
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8
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Sweetman A, Champness NR, Saywell A. On-surface chemical reactions characterised by ultra-high resolution scanning probe microscopy. Chem Soc Rev 2020; 49:4189-4202. [DOI: 10.1039/d0cs00166j] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The impact of high resolution scanning probe microscopy on imaging individual molecules with intramolecular resolution is reviewed.
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Affiliation(s)
- Adam Sweetman
- School of Physics and Astronomy
- University of Leeds
- Leeds
- UK
| | | | - Alex Saywell
- School of Physics and Astronomy
- University of Nottingham
- Nottingham
- UK
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9
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Goldmann AS, Boase NRB, Michalek L, Blinco JP, Welle A, Barner-Kowollik C. Adaptable and Reprogrammable Surfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1902665. [PMID: 31414512 DOI: 10.1002/adma.201902665] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/06/2019] [Indexed: 06/10/2023]
Abstract
Establishing control over chemical reactions on interfaces is a key challenge in contemporary surface and materials science, in particular when introducing well-defined functionalities in a reversible fashion. Reprogrammable, adaptable and functional interfaces require sophisticated chemistries to precisely equip them with specific functionalities having tailored properties. In the last decade, reversible chemistries-both covalent and noncovalent-have paved the way to precision functionalize 2 or 3D structures that provide both spatial and temporal control. A critical literature assessment reveals that methodologies for writing and erasing substrates exist, yet are still far from reaching their full potential. It is thus critical to assess the current status and to identify avenues to overcome the existing limitations. Herein, the current state-of-the-art in the field of reversible chemistry on surfaces is surveyed, while concomitantly identifying the challenges-not only synthetic but also in current surface characterization methods. The potential within reversible chemistry on surfaces to function as true writeable memories devices is identified, and the latest developments in readout technologies are discussed. Finally, we explore how spatial and temporal control over reversible, light-induced chemistries has the potential to drive the future of functional interface design, especially when combined with powerful laser lithographic applications.
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Affiliation(s)
- Anja S Goldmann
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - Nathan R B Boase
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - Lukas Michalek
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - James P Blinco
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - Alexander Welle
- Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Christopher Barner-Kowollik
- School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
- Macromolecular Architectures, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT), Engesserstr. 18, 76131, Karlsruhe, Germany
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10
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Huber F, Berwanger J, Polesya S, Mankovsky S, Ebert H, Giessibl FJ. Chemical bond formation showing a transition from physisorption to chemisorption. Science 2019; 366:235-238. [PMID: 31515246 DOI: 10.1126/science.aay3444] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 08/29/2019] [Indexed: 11/02/2022]
Abstract
Surface molecules can transition from physisorption through weak van der Waals forces to a strongly bound chemisorption state by overcoming an energy barrier. We show that a carbon monoxide (CO) molecule adsorbed to the tip of an atomic force microscope enables a controlled observation of bond formation, including its potential transition from physisorption to chemisorption. During imaging of copper (Cu) and iron (Fe) adatoms on a Cu(111) surface, the CO was not chemically inert but transited through a physisorbed local energy minimum into a chemisorbed global minimum, and an energy barrier was seen for the Fe adatom. Density functional theory reveals that the transition occurs through a hybridization of the electronic states of the CO molecule mainly with s-, p z -, and d z 2-type states of the Fe and Cu adatoms, leading to chemical bonding.
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Affiliation(s)
- Ferdinand Huber
- Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Julian Berwanger
- Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Svitlana Polesya
- Department of Chemistry, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Sergiy Mankovsky
- Department of Chemistry, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Hubert Ebert
- Department of Chemistry, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Franz J Giessibl
- Institute of Experimental and Applied Physics, Department of Physics, University of Regensburg, 93040 Regensburg, Germany.
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11
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Fan D, Sakai Y, Chelikowsky JR. Discrimination of Bond Order in Organic Molecules Using Noncontact Atomic Force Microscopy. NANO LETTERS 2019; 19:5562-5567. [PMID: 31340648 DOI: 10.1021/acs.nanolett.9b02097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Noncontact atomic force microscopy (nc-AFM) with a CO-functionalized tip can image submolecular structures through high-resolution images with the possibility of discriminating bond order. We employ real-space pseudopotential calculations to simulate nc-AFM images of molecules containing double (dibenzo(cd,n)naphtho(3,2,1,8-pqra)perylene (DBNP), hexabenzo(bc,ef,hi,kl,no,qr)coronene (HBC)) and triple (1,2-bis[2-(2-ethynylphenyl)ethynyl]-benzene (BEEB), 6-phenylhexa-1,3,5-triynylbenzene (PHTB)) bonds. We find (1) triple bonds can be unambiguously distinguished from other interatomic interactions based on a characteristic image and (2) the degree of double bond character can be directly determined from the image. We propose that large lateral forces acting on the tip may induce specific image distortions in the cases of DBNP and BEEB.
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12
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Kezilebieke S, Žitko R, Dvorak M, Ojanen T, Liljeroth P. Observation of Coexistence of Yu-Shiba-Rusinov States and Spin-Flip Excitations. NANO LETTERS 2019; 19:4614-4619. [PMID: 31251066 PMCID: PMC6628613 DOI: 10.1021/acs.nanolett.9b01583] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/05/2019] [Indexed: 06/09/2023]
Abstract
We investigate the spectral evolution in different metal phthalocyanine molecules on NbSe2 surface using scanning tunnelling microscopy (STM) as a function of the coupling with the substrate. For manganese phthalocyanine (MnPc), we demonstrate a smooth spectral crossover from Yu-Shiba-Rusinov (YSR) bound states to spin-flip excitations. This has not been observed previously and it is in contrast to simple theoretical expectations. We corroborate the experimental findings using numerical renormalization group calculations. Our results provide fundamental new insight on the behavior of atomic scale magnetic/SC hybrid systems, which is important, for example, for engineered topological superconductors and spin logic devices.
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Affiliation(s)
| | - Rok Žitko
- Jožef
Stefan Institute, Jamova 39, SI-1001 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska
19, SI-1000 Ljubljana, Slovenia
| | - Marc Dvorak
- Department
of Applied Physics, Aalto University School
of Science, 00076 Aalto, Finland
| | - Teemu Ojanen
- Department
of Applied Physics, Aalto University School
of Science, 00076 Aalto, Finland
- Computational
Physics Laboratory, Physics Unit, Faculty of Engineering and Natural
Sciences, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Peter Liljeroth
- Department
of Applied Physics, Aalto University School
of Science, 00076 Aalto, Finland
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13
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Martin-Jimenez D, Ahles S, Mollenhauer D, Wegner HA, Schirmeisen A, Ebeling D. Bond-Level Imaging of the 3D Conformation of Adsorbed Organic Molecules Using Atomic Force Microscopy with Simultaneous Tunneling Feedback. PHYSICAL REVIEW LETTERS 2019; 122:196101. [PMID: 31144947 DOI: 10.1103/physrevlett.122.196101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Indexed: 06/09/2023]
Abstract
The chemical structure and orientation of molecules on surfaces can be visualized using low temperature atomic force microscopy with CO-functionalized tips. Conventionally, this is done in constant-height mode by measuring the frequency shift of the oscillating force sensor. However, this method is unsuitable for analyzing 3D objects. We are using the tunneling current to track the topography while simultaneously obtaining submolecular resolution from the frequency shift signal. Thereby, the conformation of 3D molecules and the adsorption sites on the atomic lattice can be reliably determined.
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Affiliation(s)
- Daniel Martin-Jimenez
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Sebastian Ahles
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Doreen Mollenhauer
- Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Hermann A Wegner
- Institute of Organic Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Andre Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
- Center for Materials Research (LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany
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14
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Sun J, Chang K, Mei D, Lu Z, Pu J, Xue Q, Huang Q, Wang L, Du S. Mutual Identification between the Pressure-Induced Superlubricity and the Image Contrast Inversion of Carbon Nanostructures from AFM Technology. J Phys Chem Lett 2019; 10:1498-1504. [PMID: 30835469 DOI: 10.1021/acs.jpclett.9b00155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Previous studies predict pressure-induced superlubricity, but that is still undetermined due to the absence of a probing technique. Here, we present unprecedented mutual identification between the superlubricity and atomic-scale image from atomic force microscopy (AFM) measurement by the first-principles simulation of metallic Cu tip scanning on carbon nanostructures. With decreasing tip height, the sliding potential evolves from anticorrugated, to substantially flattened, and eventually to corrugated patterns, inducing superlubricity of the flattened potential at the critical height. Correspondingly, both the normal forces and the contrast of atomic image patterns also undergo similar inversions at the respective critical tip heights, in accordance with recent experimental observation. On the basis of the underlying mechanism elucidated, the mutual identification between the image contrast inversion and the superlubricity is confirmed. This may advance AFM technology to stimulate the experimental observation of superlubricity from its theoretical studies and may thus promote the development of theory systems of superlubticity.
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Affiliation(s)
- Junhui Sun
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
- Engineering Laboratory of Nuclear Energy Materials , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
- State Key Laboratory of Solid Lubrication , Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000 , China
- School of Mechanical Engineering, State Key Laboratory of Traction Power , Southwest Jiaotong University , Chengdu 610031 , China
| | - Keke Chang
- Engineering Laboratory of Nuclear Energy Materials , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
| | - Daohong Mei
- School of Science , East China University of Technology , Nanchang 330044 , China
| | - Zhibin Lu
- State Key Laboratory of Solid Lubrication , Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000 , China
| | - Jibin Pu
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
| | - Qunji Xue
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
- State Key Laboratory of Solid Lubrication , Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences , Lanzhou 730000 , China
| | - Qing Huang
- Engineering Laboratory of Nuclear Energy Materials , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
| | - Liping Wang
- Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
| | - Shiyu Du
- Engineering Laboratory of Nuclear Energy Materials , Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , Ningbo 315201 , China
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15
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Giessibl FJ. The qPlus sensor, a powerful core for the atomic force microscope. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:011101. [PMID: 30709191 DOI: 10.1063/1.5052264] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 12/25/2018] [Indexed: 05/27/2023]
Abstract
Atomic force microscopy (AFM) was introduced in 1986 and has since made its way into surface science, nanoscience, chemistry, biology, and material science as an imaging and manipulating tool with a rising number of applications. AFM can be employed in ambient and liquid environments as well as in vacuum and at low and ultralow temperatures. The technique is an offspring of scanning tunneling microscopy (STM), where the tunneling tip of the STM is replaced by using a force sensor with an attached tip. Measuring the tiny chemical forces that act between the tip and the sample is more difficult than measuring the tunneling current in STM. Therefore, even 30 years after the introduction of AFM, progress in instrumentation is substantial. Here, we focus on the core of the AFM, the force sensor with its tip and detection mechanism. Initially, force sensors were mainly micro-machined silicon cantilevers, mainly using optical methods to detect their deflection. The qPlus sensor, originally based on a quartz tuning fork and now custom built from quartz, is self-sensing by utilizing the piezoelectricity of quartz. The qPlus sensor allows us to perform STM and AFM in parallel, and the spatial resolution of its AFM channel has reached the subatomic level, exceeding the resolution of STM. Frequency modulation AFM (FM-AFM), where the frequency of an oscillating cantilever is altered by the gradient of the force that acts between the tip and the sample, has emerged over the years as the method that provides atomic and subatomic spatial resolution as well as force spectroscopy with sub-piconewton sensitivity. FM-AFM is precise; because of all physical observables, time and frequency can be measured by far with the greatest accuracy. By design, FM-AFM clearly separates conservative and dissipative interactions where conservative forces induce a frequency shift and dissipative interactions alter the power needed to maintain a constant oscillation amplitude of the cantilever. As it operates in a noncontact mode, it enables simultaneous AFM and STM measurements. The frequency stability of quartz and the small oscillation amplitudes that are possible with stiff quartz sensors optimize the signal to noise ratio. Here, we discuss the operating principles, the assembly of qPlus sensors, amplifiers, limiting factors, and applications. Applications encompass unprecedented subatomic spatial resolution, the measurement of forces that act in atomic manipulation, imaging and spectroscopy of spin-dependent forces, and atomic resolution of organic molecules, graphite, graphene, and oxides.
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Affiliation(s)
- Franz J Giessibl
- Institute of Experimental and Applied Physics, University of Regensburg, Universitätsstrasse 31, D-93040 Regensburg, Germany
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16
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Jadidi MF, Kamber U, Gürlü O, Özer HÖ. Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:2953-2959. [PMID: 30546992 PMCID: PMC6278757 DOI: 10.3762/bjnano.9.274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) images of graphene reveal either a triangular or honeycomb pattern at the atomic scale depending on the imaging parameters. The triangular patterns at the atomic scale are particularly difficult to interpret, as the maxima in the images could be every other carbon atom in the six-fold hexagonal array or even a hollow site. Carbon sites exhibit an inequivalent electronic structure in HOPG or multilayer graphene due to the presence of a carbon atom or a hollow site underneath. In this work, we report small-amplitude, simultaneous STM/AFM imaging using a metallic (tungsten) tip, of the graphene surface as-grown by chemical vapor deposition (CVD) on Cu foils. Truly simultaneous operation is possible only with the use of small oscillation amplitudes. Under a typical STM imaging regime the force interaction is found to be repulsive. Force-distance spectroscopy revealed a maximum attractive force of about 7 nN between the tip and carbon/hollow sites. We obtained different contrast between force and STM topography images for atomic features. A honeycomb pattern showing all six carbon atoms is revealed in AFM images. In one contrast type, simultaneously acquired STM topography revealed hollow sites to be brighter. In another, a triangular array with maxima located in between the two carbon atoms was acquired in STM topography.
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Affiliation(s)
- Majid Fazeli Jadidi
- Department of Physics Engineering, İstanbul Technical University, 34469, İstanbul, Turkey
| | - Umut Kamber
- Department of Physics Engineering, İstanbul Technical University, 34469, İstanbul, Turkey
| | - Oğuzhan Gürlü
- Department of Physics Engineering, İstanbul Technical University, 34469, İstanbul, Turkey
| | - H Özgür Özer
- Department of Physics Engineering, İstanbul Technical University, 34469, İstanbul, Turkey
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17
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Liu X, Hersam MC. Interface Characterization and Control of 2D Materials and Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1801586. [PMID: 30039558 DOI: 10.1002/adma.201801586] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 04/09/2018] [Indexed: 05/28/2023]
Abstract
2D materials and heterostructures have attracted significant attention for a variety of nanoelectronic and optoelectronic applications. At the atomically thin limit, the material characteristics and functionalities are dominated by surface chemistry and interface coupling. Therefore, methods for comprehensively characterizing and precisely controlling surfaces and interfaces are required to realize the full technological potential of 2D materials. Here, the surface and interface properties that govern the performance of 2D materials are introduced. Then the experimental approaches that resolve surface and interface phenomena down to the atomic scale, as well as strategies that allow tuning and optimization of interfacial interactions in van der Waals heterostructures, are systematically reviewed. Finally, a future outlook that delineates the remaining challenges and opportunities for 2D material interface characterization and control is presented.
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Affiliation(s)
- Xiaolong Liu
- Applied Physics Graduate Program, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208-3108, USA
| | - Mark C Hersam
- Applied Physics Graduate Program, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208-3108, USA
- Department of Materials Science and Engineering, Department of Chemistry, Department of Medicine, Department of Electrical Engineering and Computer Science, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208-3108, USA
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18
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Zhong Q, Ebeling D, Tschakert J, Gao Y, Bao D, Du S, Li C, Chi L, Schirmeisen A. Symmetry breakdown of 4,4″-diamino-p-terphenyl on a Cu(111) surface by lattice mismatch. Nat Commun 2018; 9:3277. [PMID: 30115915 PMCID: PMC6095862 DOI: 10.1038/s41467-018-05719-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 07/24/2018] [Indexed: 11/13/2022] Open
Abstract
Site-selective functionalization of only one of two identical chemical groups within one molecule is highly challenging, which hinders the production of complex organic macromolecules. Here we demonstrate that adsorption of 4,4″-diamino-p-terphenyl on a metal surface leads to a dissymmetric binding affinity. With low temperature atomic force microscopy, using CO-tip functionalization, we reveal the asymmetric adsorption geometries of 4,4″-diamino-p-terphenyl on Cu(111), while on Au(111) the symmetry is retained. This symmetry breaking on Cu(111) is caused by a lattice mismatch and interactions with the subsurface atomic layer. The dissymmetry results in a change of the binding affinity of one of the amine groups, leading to a non-stationary behavior under the influence of the scanning tip. Finally, we exploit this dissymmetric binding affinity for on-surface self-assembly with 4,4″-diamino-p-terphenyl for side-preferential attachment of 2-triphenylenecarbaldehyde. Our findings provide a new route towards surface-induced dissymmetric activation of a symmetric compound. In a symmetric molecule with identical functional groups, selective activation of only one site is challenging. Here, the authors show that 4,4″-diamino-p-terphenyl adsorbs asymmetrically to a metal surface, leading to a change in binding affinity of one of its amine groups.
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Affiliation(s)
- Qigang Zhong
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China
| | - Daniel Ebeling
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany.
| | - Jalmar Tschakert
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
| | - Yixuan Gao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Deliang Bao
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Shixuan Du
- Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
| | - Chen Li
- School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan, 523808, P. R. China
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, P. R. China.
| | - André Schirmeisen
- Institute of Applied Physics, Justus-Liebig University, Heinrich-Buff-Ring 16, 35392, Giessen, Germany
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19
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Schulz F, Ritala J, Krejčí O, Seitsonen AP, Foster AS, Liljeroth P. Elemental Identification by Combining Atomic Force Microscopy and Kelvin Probe Force Microscopy. ACS NANO 2018; 12:5274-5283. [PMID: 29800512 PMCID: PMC6097802 DOI: 10.1021/acsnano.7b08997] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/25/2018] [Indexed: 05/23/2023]
Abstract
There are currently no experimental techniques that combine atomic-resolution imaging with elemental sensitivity and chemical fingerprinting on single molecules. The advent of using molecular-modified tips in noncontact atomic force microscopy (nc-AFM) has made it possible to image (planar) molecules with atomic resolution. However, the mechanisms responsible for elemental contrast with passivated tips are not fully understood. Here, we investigate elemental contrast by carrying out both nc-AFM and Kelvin probe force microscopy (KPFM) experiments on epitaxial monolayer hexagonal boron nitride (hBN) on Ir(111). The hBN overlayer is inert, and the in-plane bonds connecting nearest-neighbor boron and nitrogen atoms possess strong covalent character and a bond length of only ∼1.45 Å. Nevertheless, constant-height maps of both the frequency shift Δ f and the local contact potential difference exhibit striking sublattice asymmetry. We match the different atomic sites with the observed contrast by comparison with nc-AFM image simulations based on the density functional theory optimized hBN/Ir(111) geometry, which yields detailed information on the origin of the atomic-scale contrast.
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Affiliation(s)
- Fabian Schulz
- Department
of Applied Physics, Aalto University School
of Science, P.O. Box 15100, FI-00076 Aalto, Finland
| | - Juha Ritala
- COMP
Center of Excellence, Department of Applied Physics, Aalto University School of Science,
P.O. Box 11100, FI-00076 Aalto, Finland
| | - Ondrej Krejčí
- COMP
Center of Excellence, Department of Applied Physics, Aalto University School of Science,
P.O. Box 11100, FI-00076 Aalto, Finland
| | - Ari Paavo Seitsonen
- Département
de Chimie, École Normale Supérieure, 24 rue Lhomond, F-75005 Paris, France
| | - Adam S. Foster
- COMP
Center of Excellence, Department of Applied Physics, Aalto University School of Science,
P.O. Box 11100, FI-00076 Aalto, Finland
- WPI
Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
- Graduate
School Materials Science in Mainz, Staudinger Weg 9, D-55128 Mainz, Germany
| | - Peter Liljeroth
- Department
of Applied Physics, Aalto University School
of Science, P.O. Box 15100, FI-00076 Aalto, Finland
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20
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Zint S, Ebeling D, Schlöder T, Ahles S, Mollenhauer D, Wegner HA, Schirmeisen A. Imaging Successive Intermediate States of the On-Surface Ullmann Reaction on Cu(111): Role of the Metal Coordination. ACS NANO 2017; 11:4183-4190. [PMID: 28346826 DOI: 10.1021/acsnano.7b01109] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The in-depth knowledge about on-surface reaction mechanisms is crucial for the tailor-made design of covalently bonded organic frameworks, for applications such as nanoelectronic or -optical devices. Latest developments in atomic force microscopy, which rely on functionalizing the tip with single CO molecules at low temperatures, allow to image molecular systems with submolecular resolution. Here, we are using this technique to study the complete reaction pathway of the on-surface Ullmann-type coupling between bromotriphenylene molecules on a Cu(111) surface. All steps of the Ullmann reaction, i.e., bromotriphenylenes, triphenylene radicals, organometallic intermediates, and bistriphenylenes, were imaged with submolecular resolution. Together with density functional theory calculations with dispersion correction, our study allows to address the long-standing question of how the organometallic intermediates are coordinated via Cu surface or adatoms.
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Affiliation(s)
- Sören Zint
- Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | - Daniel Ebeling
- Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
| | | | | | | | | | - André Schirmeisen
- Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany
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21
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Labidi H, Koleini M, Huff T, Salomons M, Cloutier M, Pitters J, Wolkow RA. Indications of chemical bond contrast in AFM images of a hydrogen-terminated silicon surface. Nat Commun 2017; 8:14222. [PMID: 28194036 PMCID: PMC5316802 DOI: 10.1038/ncomms14222] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 12/08/2016] [Indexed: 01/05/2023] Open
Abstract
The origin of bond-resolved atomic force microscope images remains controversial. Moreover, most work to date has involved planar, conjugated hydrocarbon molecules on a metal substrate thereby limiting knowledge of the generality of findings made about the imaging mechanism. Here we report the study of a very different sample; a hydrogen-terminated silicon surface. A procedure to obtain a passivated hydrogen-functionalized tip is defined and evolution of atomic force microscopy images at different tip elevations are shown. At relatively large tip-sample distances, the topmost atoms appear as distinct protrusions. However, on decreasing the tip-sample distance, features consistent with the silicon covalent bonds of the surface emerge. Using a density functional tight-binding-based method to simulate atomic force microscopy images, we reproduce the experimental results. The role of the tip flexibility and the nature of bonds and false bond-like features are discussed. Whether and under what circumstances chemical bonds could be imaged via force microscopy is a controversial topic. Here authors develop a particular combination of model surface, imaging procedures and simulation approach and discuss possible indications of chemical contrast in imaging data they obtain.
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Affiliation(s)
- Hatem Labidi
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2J1.,National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9
| | - Mohammad Koleini
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2J1.,National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9
| | - Taleana Huff
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2J1
| | - Mark Salomons
- National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9
| | - Martin Cloutier
- National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9
| | - Jason Pitters
- National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9
| | - Robert A Wolkow
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2J1.,National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta, Canada T6G 2M9
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22
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Dagdeviren OE, Götzen J, Altman EI, Schwarz UD. Exploring site-specific chemical interactions at surfaces: a case study on highly ordered pyrolytic graphite. NANOTECHNOLOGY 2016; 27:485708. [PMID: 27811384 DOI: 10.1088/0957-4484/27/48/485708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A material's ability to interact with approaching matter is governed by the structural and chemical nature of its surfaces. Tailoring surfaces to meet specific needs requires developing an understanding of the underlying fundamental principles that determine a surface's reactivity. A particularly insightful case occurs when the surface site exhibiting the strongest attraction changes with distance. To study this issue, combined noncontact atomic force microscopy and scanning tunneling microscopy experiments have been carried out, where the evolution of the local chemical interaction with distance leads to a contrast reversal in the force channel. Using highly ordered pyrolytic graphite surfaces and metallic probe tips as a model system, we find that at larger tip-sample distances, carbon atoms exhibit stronger attractions than hollow sites while upon further approach, hollow sites become energetically more favorable. For the tunneling current that is recorded at large tip-sample separations during acquisition of a constant-force image, the contrast is dominated by the changes in tip-sample distance required to hold the force constant ('cross-talk'); at smaller separations the contrast turns into a convolution of this cross-talk and the local density of states. Analysis shows that the basic factors influencing the force channel contrast reversal are locally varying decay lengths and an onset of repulsive forces that occurs for distinct surface sites at different tip-sample distances. These findings highlight the importance of tip-sample distance when comparing the relative strength of site-specific chemical interactions.
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Affiliation(s)
- Omur E Dagdeviren
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA. Center for Research on Interface Structures and Phenomena (CRISP), Yale University, New Haven, CT 06520, USA
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23
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Niu YP, Lin XH, Dong SJ, Yuan QP, Li H. Indentation with atomic force microscope, Saccharomyces cerevisiae cell gains elasticity under ethanol stress. Int J Biochem Cell Biol 2016; 79:337-344. [PMID: 27613572 DOI: 10.1016/j.biocel.2016.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 08/09/2016] [Accepted: 09/02/2016] [Indexed: 12/23/2022]
Abstract
During bioethanol fermentation process, Saccharomyces cerevisiae cell membrane is the first target to be attacked by the accumulated ethanol. In such a prominent position, S. cerevisiae cell membrane could reversely provide protection through changing fluidity or elasticity secondary to remodeled membrane components or structure during the fermentation process. However, there is yet to be a direct observation of the real effect of the membrane compositional change. In this study, atomic force microscope-based strategy was performed to determine Young's modulus of S. cerevisiae to directly clarify ethanol stress-associated changes and roles of S. cerevisiae cell membrane fluidity and elasticity. Cell survival rate decreased while the cell swelling rate and membrane permeability increased as ethanol concentration increased from 0% to 20% v/v. Young's modulus decreased continuously from 3.76MPa to 1.53MPa while ethanol stress increased from 0% to 20% v/v, indicating that ethanol stress induced the S. cerevisiae membrane fluidity and elasticity changes. Combined with the fact that membrane composition varies under ethanol stress, to some extent, this could be considered as a forced defensive act to the ethanol stress by S. cerevisiae cells. On the other hand, the ethanol stress induced loosening of cell membrane also caused S. cerevisiae cell to proactively remodel membrane to make cell membrane more agreeable to the increase of environmental threat. Increased ethanol stress made S. cerevisiae cell membrane more fluidized and elastic, and eventually further facilitated yeast cell's survival.
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Affiliation(s)
- Yuan-Pu Niu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Xiang-Hua Lin
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Shi-Jun Dong
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Qi-Peng Yuan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China
| | - Hao Li
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
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24
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Song Q, Pan X, Wang H, Zhang K, Tan Q, Li P, Wan Y, Wang Y, Xu X, Lin M, Wan X, Song F, Dai L. The In-Plane Anisotropy of WTe2 Investigated by Angle-Dependent and Polarized Raman Spectroscopy. Sci Rep 2016; 6:29254. [PMID: 27404226 PMCID: PMC4941539 DOI: 10.1038/srep29254] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/15/2016] [Indexed: 11/27/2022] Open
Abstract
Tungsten ditelluride (WTe2) is a semi-metallic layered transition metal dichalcogenide with a stable distorted 1T phase. The reduced symmetry of this system leads to in-plane anisotropy in various materials properties. We have systemically studied the in-plane anisotropy of Raman modes in few-layer and bulk WTe2 by angle-dependent and polarized Raman spectroscopy (ADPRS). Ten Raman modes are clearly resolved. Their intensities show periodic variation with sample rotating. We identify the symmetries of the detected modes by quantitatively analyzing the ADPRS results based on the symmetry selection rules. Material absorption effect on the phonon modes with high vibration frequencies is investigated by considering complex Raman tensor elements. We also provide a rapid and nondestructive method to identify the crystallographic orientation of WTe2. The crystallographic orientation is further confirmed by the quantitative atomic-resolution force image. Finally, we find that the atomic vibrational tendency and complexity of detected modes are also reflected in the shrinkage degree defined based on ADPRS, which is confirmed by corresponding density functional calculation. Our work provides a deep understanding of the interaction between WTe2 and light, which will benefit in future studies about the anisotropic physical properties of WTe2 and other in-plane anisotropic materials.
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Affiliation(s)
- Qingjun Song
- State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing, 100871, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Xingchen Pan
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing, 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Haifeng Wang
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing, 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Kun Zhang
- State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing, 100871, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Qinghai Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Pan Li
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Yi Wan
- State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing, 100871, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Yilun Wang
- State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing, 100871, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Xiaolong Xu
- State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing, 100871, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
| | - Miaoling Lin
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Xiangang Wan
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing, 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Fengqi Song
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing, 210093, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Lun Dai
- State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing, 100871, China.,Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China
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25
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de la Torre B, Ellner M, Pou P, Nicoara N, Pérez R, Gómez-Rodríguez JM. Atomic-Scale Variations of the Mechanical Response of 2D Materials Detected by Noncontact Atomic Force Microscopy. PHYSICAL REVIEW LETTERS 2016; 116:245502. [PMID: 27367394 DOI: 10.1103/physrevlett.116.245502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 06/06/2023]
Abstract
We show that noncontact atomic force microscopy (AFM) is sensitive to the local stiffness in the atomic-scale limit on weakly coupled 2D materials, as graphene on metals. Our large amplitude AFM topography and dissipation images under ultrahigh vacuum and low temperature resolve the atomic and moiré patterns in graphene on Pt(111), despite its extremely low geometric corrugation. The imaging mechanisms are identified with a multiscale model based on density-functional theory calculations, where the energy cost of global and local deformations of graphene competes with short-range chemical and long-range van der Waals interactions. Atomic contrast is related with short-range tip-sample interactions, while the dissipation can be understood in terms of global deformations in the weakly coupled graphene layer. Remarkably, the observed moiré modulation is linked with the subtle variations of the local interplanar graphene-substrate interaction, opening a new route to explore the local mechanical properties of 2D materials at the atomic scale.
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Affiliation(s)
- B de la Torre
- Departamento de Fisica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - M Ellner
- Departamento de Fisica Teorica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - P Pou
- Departamento de Fisica Teorica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - N Nicoara
- Departamento de Fisica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- International Iberian Nanotechnology Laboratory, 4715-310 Braga, Portugal
| | - Rubén Pérez
- Departamento de Fisica Teorica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - J M Gómez-Rodríguez
- Departamento de Fisica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
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26
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Sakai Y, Lee AJ, Chelikowsky JR. First-Principles Atomic Force Microscopy Image Simulations with Density Embedding Theory. NANO LETTERS 2016; 16:3242-3246. [PMID: 27050710 DOI: 10.1021/acs.nanolett.6b00741] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present an efficient first-principles method for simulating noncontact atomic force microscopy (nc-AFM) images using a "frozen density" embedding theory. Frozen density embedding theory enables one to efficiently compute the tip-sample interaction by considering a sample as a frozen external field. This method reduces the extensive computational load of first-principles AFM simulations by avoiding consideration of the entire tip-sample system and focusing on the tip alone. We demonstrate that our simulation with frozen density embedding theory accurately reproduces full density functional theory simulations of freestanding hydrocarbon molecules while the computational time is significantly reduced. Our method also captures the electronic effect of a Cu(111) substrate on the AFM image of pentacene and reproduces the experimental AFM image of Cu2N on a Cu(100) surface. This approach is applicable for theoretical imaging applications on large molecules, two-dimensional materials, and materials surfaces.
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Affiliation(s)
- Yuki Sakai
- Center for Computational Materials, Institute for Computational Engineering and Sciences, ‡Department of Chemical Engineering, §Department of Physics, The University of Texas at Austin , Austin, Texas 78712, United States
| | - Alex J Lee
- Center for Computational Materials, Institute for Computational Engineering and Sciences, ‡Department of Chemical Engineering, §Department of Physics, The University of Texas at Austin , Austin, Texas 78712, United States
| | - James R Chelikowsky
- Center for Computational Materials, Institute for Computational Engineering and Sciences, ‡Department of Chemical Engineering, §Department of Physics, The University of Texas at Austin , Austin, Texas 78712, United States
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27
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van der Lit J, Di Cicco F, Hapala P, Jelinek P, Swart I. Submolecular Resolution Imaging of Molecules by Atomic Force Microscopy: The Influence of the Electrostatic Force. PHYSICAL REVIEW LETTERS 2016; 116:096102. [PMID: 26991186 DOI: 10.1103/physrevlett.116.096102] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Indexed: 05/24/2023]
Abstract
The forces governing the contrast in submolecular resolution imaging of molecules with atomic force microscopy (AFM) have recently become a topic of intense debate. Here, we show that the electrostatic force is essential to understand the contrast in atomically resolved AFM images of polar molecules. Specifically, we image strongly polarized molecules with negatively and positively charged tips. A contrast inversion is observed above the polar groups. By taking into account the electrostatic forces between tip and molecule, the observed contrast differences can be reproduced using a molecular mechanics model. In addition, we analyze the height dependence of the various force components contributing to the high-resolution AFM contrast.
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Affiliation(s)
- Joost van der Lit
- Debye Institute for Nanomaterials Science, Utrecht University, P.O. Box 80.000, 3508 TA Utrecht, The Netherlands
| | - Francesca Di Cicco
- Debye Institute for Nanomaterials Science, Utrecht University, P.O. Box 80.000, 3508 TA Utrecht, The Netherlands
| | - Prokop Hapala
- Institute of Physics, Academy of Sciences of the Czech Republic Cukrovarnicka 10, 1862 53 Prague, Czech Republic
| | - Pavel Jelinek
- Institute of Physics, Academy of Sciences of the Czech Republic Cukrovarnicka 10, 1862 53 Prague, Czech Republic
| | - Ingmar Swart
- Debye Institute for Nanomaterials Science, Utrecht University, P.O. Box 80.000, 3508 TA Utrecht, The Netherlands
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28
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Martínez JI, Merino P, Pinardi AL, Gonzalo OI, López MF, Méndez J, Martín-Gago JA. Role of the Pinning Points in epitaxial Graphene Moiré Superstructures on the Pt(111) Surface. Sci Rep 2016; 6:20354. [PMID: 26852920 PMCID: PMC4745011 DOI: 10.1038/srep20354] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 12/30/2015] [Indexed: 01/22/2023] Open
Abstract
The intrinsic atomic mechanisms responsible for electronic doping of epitaxial graphene Moirés on transition metal surfaces is still an open issue. To better understand this process we have carried out a first-principles full characterization of the most representative Moiré superstructures observed on the Gr/Pt(111) system and confronted the results with atomically resolved scanning tunneling microscopy experiments. We find that for all reported Moirés the system relaxes inducing a non-negligible atomic corrugation both, at the graphene and at the outermost platinum layer. Interestingly, a mirror “anti-Moiré” reconstruction appears at the substrate, giving rise to the appearance of pinning-points. We show that these points are responsible for the development of the superstructure, while charge from the Pt substrate is injected into the graphene, inducing a local n-doping, mostly localized at these specific pinning-point positions.
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Affiliation(s)
- José I Martínez
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - Pablo Merino
- Center for Astrobiology (INTA-CSIC), Torrejón de Ardoz, 28850 Madrid, Spain
| | - Anna L Pinardi
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - Otero-Irurueta Gonzalo
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.,Center for Mechanical Technology and Automation (TEMA), University of Aveiro, 3810-193 Aveiro, Portugal
| | - María F López
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - Javier Méndez
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - José A Martín-Gago
- ESISNA Group, Dept. Surfaces, Coatings and Molecular Astrophysics, Institute of Material Science of Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain.,Center for Astrobiology (INTA-CSIC), Torrejón de Ardoz, 28850 Madrid, Spain
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29
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Süle P, Szendrő M, Magda GZ, Hwang C, Tapasztó L. Nanomesh-Type Graphene Superlattice on Au(111) Substrate. NANO LETTERS 2015; 15:8295-8299. [PMID: 26560972 DOI: 10.1021/acs.nanolett.5b03886] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The adherence of graphene to various crystalline substrates often leads to a periodic out-of-plane modulation of its atomic structure due to the lattice mismatch. While, in principle, convex (protrusion) and concave (depression) superlattice geometries are nearly equivalent, convex superlattices have predominantly been observed for graphene on various metal surfaces. Here we report the STM observation of a graphene superlattice with concave (nanomesh) morphology on Au(111). DFT and molecular dynamics simulations confirm the nanomesh nature of the graphene superlattice on Au(111) and also reveal its potential origin as a surface reconstruction, consisting of the imprinting of the nanomesh morphology into the Au(111) surface. This unusual surface reconstruction can be attributed to the particularly large mobility of the Au atoms on Au(111) surfaces and most probably plays an important role in stabilizing the concave graphene superlattice. We report the simultaneous observation of both convex and concave graphene superlattices on herringbone reconstructed Au(111) excluding the contrast inversion as the origin of the observed concave morphology. The observed graphene nanomesh superlattice can provide an intriguing nanoscale template for self-assembled structures and nanoparticles that cannot be stabilized on other surfaces.
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Affiliation(s)
- Péter Süle
- Institute for Technical Physics and Materials Science, Centre for Energy Research Konkoly Thege u. 29-33, Budapest, Hungary
| | - Márton Szendrő
- Institute for Technical Physics and Materials Science, Centre for Energy Research Konkoly Thege u. 29-33, Budapest, Hungary
| | - Gábor Zsolt Magda
- 2D Nanoelectronics "Lendület" Research Group, Institute for Technical Physics and Materials Science, Centre for Energy Research , Konkoly Thege u. 29-33, Budapest, Hungary
| | - Chanyong Hwang
- Center for Nanometrology, Korea Research Institute of Standards and Science , Daejeon 305-340, Republic of Korea
| | - Levente Tapasztó
- 2D Nanoelectronics "Lendület" Research Group, Institute for Technical Physics and Materials Science, Centre for Energy Research , Konkoly Thege u. 29-33, Budapest, Hungary
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30
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Jarvis SP. Resolving Intra- and Inter-Molecular Structure with Non-Contact Atomic Force Microscopy. Int J Mol Sci 2015; 16:19936-59. [PMID: 26307976 PMCID: PMC4581333 DOI: 10.3390/ijms160819936] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 07/24/2015] [Accepted: 07/30/2015] [Indexed: 11/25/2022] Open
Abstract
A major challenge in molecular investigations at surfaces has been to image individual molecules, and the assemblies they form, with single-bond resolution. Scanning probe microscopy, with its exceptionally high resolution, is ideally suited to this goal. With the introduction of methods exploiting molecularly-terminated tips, where the apex of the probe is, for example, terminated with a single CO, Xe or H2 molecule, scanning probe methods can now achieve higher resolution than ever before. In this review, some of the landmark results related to attaining intramolecular resolution with non-contact atomic force microscopy (NC-AFM) are summarised before focussing on recent reports probing molecular assemblies where apparent intermolecular features have been observed. Several groups have now highlighted the critical role that flexure in the tip-sample junction plays in producing the exceptionally sharp images of both intra- and apparent inter-molecular structure. In the latter case, the features have been identified as imaging artefacts, rather than real intermolecular bonds. This review discusses the potential for NC-AFM to provide exceptional resolution of supramolecular assemblies stabilised via a variety of intermolecular forces and highlights the potential challenges and pitfalls involved in interpreting bonding interactions.
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Affiliation(s)
- Samuel Paul Jarvis
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
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31
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Gross L, Schuler B, Mohn F, Moll N, Repp J, Meyer G. Atomic Resolution on Molecules with Functionalized Tips. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/978-3-319-15588-3_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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32
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Moreno C, Stetsovych O, Shimizu TK, Custance O. Imaging three-dimensional surface objects with submolecular resolution by atomic force microscopy. NANO LETTERS 2015; 15:2257-62. [PMID: 25756297 DOI: 10.1021/nl504182w] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Submolecular imaging by atomic force microscopy (AFM) has recently been established as a stunning technique to reveal the chemical structure of unknown molecules, to characterize intramolecular charge distributions and bond ordering, as well as to study chemical transformations and intermolecular interactions. So far, most of these feats were achieved on planar molecular systems because high-resolution imaging of three-dimensional (3D) surface structures with AFM remains challenging. Here we present a method for high-resolution imaging of nonplanar molecules and 3D surface systems using AFM with silicon cantilevers as force sensors. We demonstrate this method by resolving the step-edges of the (101) anatase surface at the atomic scale by simultaneously visualizing the structure of a pentacene molecule together with the atomic positions of the substrate and by resolving the contour and probe-surface force field on a C60 molecule with intramolecular resolution. The method reported here holds substantial promise for the study of 3D surface systems such as nanotubes, clusters, nanoparticles, polymers, and biomolecules using AFM with high resolution.
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Affiliation(s)
- César Moreno
- †National Institute for Materials Science (NIMS), 1-2-1 Sengen, 305-0047 Tsukuba, Ibaraki Japan
- ‡International Center for Young Scientists, NIMS, 1-2-1 Sengen, 305-0047 Tsukuba, Ibaraki Japan
| | - Oleksandr Stetsovych
- †National Institute for Materials Science (NIMS), 1-2-1 Sengen, 305-0047 Tsukuba, Ibaraki Japan
- §Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, Prague, Czech Rebublic
| | - Tomoko K Shimizu
- †National Institute for Materials Science (NIMS), 1-2-1 Sengen, 305-0047 Tsukuba, Ibaraki Japan
- §JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Oscar Custance
- †National Institute for Materials Science (NIMS), 1-2-1 Sengen, 305-0047 Tsukuba, Ibaraki Japan
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33
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Telychko M, Berger J, Majzik Z, Jelínek P, Švec M. Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2015; 6:901-6. [PMID: 25977861 PMCID: PMC4419658 DOI: 10.3762/bjnano.6.93] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 03/02/2015] [Indexed: 06/04/2023]
Abstract
We investigated single-layer graphene on SiC(0001) by atomic force and tunneling current microscopy, to separate the topographic and electronic contributions from the overall landscape. The analysis revealed that the roughness evaluated from the atomic force maps is very low, in accord with theoretical simulations. We also observed that characteristic electron scattering effects on graphene edges and defects are not accompanied by any out-of-plane relaxations of carbon atoms.
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Affiliation(s)
- Mykola Telychko
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-16200 Prague, Czech Republic
- Charles University, Faculty of Mathematics and Physics, V Holešovičkách 2, Praha 8, Czech Republic
| | - Jan Berger
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-16200 Prague, Czech Republic
- Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Břehová 7, CZ-11519 Prague, Czech Republic
| | - Zsolt Majzik
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-16200 Prague, Czech Republic
| | - Pavel Jelínek
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-16200 Prague, Czech Republic
| | - Martin Švec
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-16200 Prague, Czech Republic
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34
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Meza JAM, Lubin C, Thoyer F, Cousty J. Tip induced mechanical deformation of epitaxial graphene grown on reconstructed 6H-SiC(0001) surface during scanning tunneling and atomic force microscopy studies. NANOTECHNOLOGY 2015; 26:255704. [PMID: 26040291 DOI: 10.1088/0957-4484/26/25/255704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The structural and mechanical properties of an epitaxial graphene (EG) monolayer thermally grown on top of a 6H-SiC(0001) surface were studied by combined dynamic scanning tunneling microscopy (STM) and frequency modulation atomic force microscopy (FM-AFM). Experimental STM, dynamic STM and AFM images of EG on 6H-SiC(0001) show a lattice with a 1.9 nm period corresponding to the (6 × 6) quasi-cell of the SiC surface. The corrugation amplitude of this (6 × 6) quasi-cell, measured from AFM topographies, increases with the setpoint value of the frequency shift Δf (15-20 Hz, repulsive interaction). Excitation variations map obtained simultaneously with the AFM topography shows that larger dissipation values are measured in between the topographical bumps of the (6 × 6) quasi-cell. These results demonstrate that the AFM tip deforms the graphene monolayer. During recording in dynamic STM mode, a frequency shift (Δf) map is obtained in which Δf values range from 41 to 47 Hz (repulsive interaction). As a result, we deduced that the STM tip, also, provokes local mechanical distortions of the graphene monolayer. The origin of these tip-induced distortions is discussed in terms of electronic and mechanical properties of EG on 6H-SiC(0001).
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Affiliation(s)
- José Antonio Morán Meza
- Service de Physique de l'Etat Condensé, DSM/IRAMIS/SPEC, CNRS UMR 3680, CEA Saclay, F-91191 Gif sur Yvette Cedex, France. Grupo de Materiales Nanoestructurados, Facultad de Ciencias, Universidad Nacional de Ingeniería, Av. Túpac Amaru 210, Lima 25, Peru
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35
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Mistry A, Moreton B, Schuler B, Mohn F, Meyer G, Gross L, Williams A, Scott P, Costantini G, Fox DJ. The Synthesis and STM/AFM Imaging of ‘Olympicene’ Benzo[cd]pyrenes. Chemistry 2014; 21:2011-8. [DOI: 10.1002/chem.201404877] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Indexed: 11/10/2022]
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36
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Sang H, Jarvis SP, Zhou Z, Sharp P, Moriarty P, Wang J, Wang Y, Kantorovich L. Identifying tips for intramolecular NC-AFM imaging via in situ fingerprinting. Sci Rep 2014; 4:6678. [PMID: 25327642 PMCID: PMC4202218 DOI: 10.1038/srep06678] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 09/29/2014] [Indexed: 11/09/2022] Open
Abstract
A practical experimental strategy is proposed that could potentially enable greater control of the tip apex in non-contact atomic force microscopy experiments. It is based on a preparation of a structure of interest alongside a reference surface reconstruction on the same sample. Our proposed strategy is as follows. Spectroscopy measurements are first performed on the reference surface to identify the tip apex structure using a previously collected database of responses of different tips to this surface. Next, immediately following the tip identification protocol, the surface of interest is studied (imaging, manipulation and/or spectroscopy). The prototype system we choose is the mixed Si(111)-7×7 and Ag:Si(111)-(√3 × √3) R30° surface which can be prepared on the same sample with a controlled ratio of reactive and passivated regions. Using an "in silico" approach based on ab initio density functional calculations and a set of tips with varying chemical reactivities, we show how one can perform tip fingerprinting using the Si(111)-7×7 reference surface. Then it is found by examining the imaging of a naphthalene tetracarboxylic diimide (NTCDI) molecule adsorbed on Ag:Si(111)-(√3 × √3) R30° surface that negatively charged tips produce the best intramolecular contrast attributed to the enhancement of repulsive interactions.
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Affiliation(s)
- Hongqian Sang
- School of Physics and Technology, Center 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, U.K
| | - Samuel P. Jarvis
- The School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Zhichao Zhou
- School of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, China
| | - Peter Sharp
- The School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Philip Moriarty
- The School of Physics and Astronomy, The University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Jianbo Wang
- School of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, China
| | - Yu Wang
- School of Physics and Technology, Center for Electron Microscopy and MOE Key Laboratory of Artificial Micro- and Nano-structures, Wuhan University, Wuhan 430072, China
| | - Lev Kantorovich
- Department of Physics, King's College London, The Strand, London, WC2R 2LS, U.K
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37
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Kawai S, Eren B, Marot L, Meyer E. Graphene synthesis via thermal polymerization of aromatic quinone molecules. ACS NANO 2014; 8:5932-5938. [PMID: 24873393 DOI: 10.1021/nn501047v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Graphene was synthesized from pentacenequinone molecules on a Cu(111) surface using a three-step thermal treatment process: (1) self-assembly of a single layer molecular film at 190 °C, (2) formation of covalent bonding between adjacent molecules at intermediate temperatures, (3) thermal dehydrogenation and in-plane carbon diffusion at 600 °C. Transformation of the surface conformation was monitored with bimodal atomic force microscopy at the atomic scale and was corroborated with core-level X-ray photoelectron spectroscopy. A strong C═O···H-C hydrogen bonding involving the quinone moiety plays a key role in graphene growth, whereas conventional pentacene simply desorbs from the substrate during the same process. The most significant achievement of this proposed technique is obtaining graphene a couple of hundred degrees lower than standard techniques. Intrinsic defects due to carbon deficiency and the defects intentionally introduced by the microscope tip were also investigated with atomic-scale imaging.
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Affiliation(s)
- Shigeki Kawai
- Department of Physics, University of Basel , Klingbergstrasse 82, 4056 Basel, Switzerland
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38
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Merino P, Rodrigo L, Pinardi AL, Méndez J, López MF, Pou P, Pérez R, Martín Gago JA. Sublattice localized electronic states in atomically resolved graphene-Pt(111) edge-boundaries. ACS NANO 2014; 8:3590-3596. [PMID: 24654926 DOI: 10.1021/nn500105a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Understanding the connection of graphene with metal surfaces is a necessary step for developing atomically precise graphene-based technology. Combining high-resolution STM experiments and DFT calculations, we have unambiguously unveiled the atomic structure of the boundary between a graphene zigzag edge and a Pt(111) step. The graphene edges minimize their strain by inducing a 3-fold edge-reconstruction on the metal side. We show the existence of an unoccupied electronic state that is mostly localized on the C-edge atoms of one particular graphene sublattice, which could have implications in the design of graphene based devices.
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Affiliation(s)
- Pablo Merino
- Centro de Astrobiología INTA-CSIC , Carretera de Ajalvir, km.4, E-28850 Madrid, Spain
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39
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Boneschanscher MP, Hämäläinen SK, Liljeroth P, Swart I. Sample corrugation affects the apparent bond lengths in atomic force microscopy. ACS NANO 2014; 8:3006-3014. [PMID: 24559211 DOI: 10.1021/nn500317r] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Frequency modulation atomic force microscopy (AFM) allows the chemical structure of planar molecules to be determined with atomic resolution. Typically, these measurements are carried out in constant-height mode using carbon monoxide (CO) terminated tips. Such tips exhibit considerable flexibility, i.e., the CO molecule can bend laterally due to the tip-sample interaction. Using epitaxial graphene as a model system, we demonstrate experimentally that the apparent atomic positions measured by AFM depend on the sample corrugation. Using molecular mechanics simulations, we explain these observations by the interplay of the CO bending and the nonlinear background signal arising from the neighboring atoms. These effects depend nontrivially on the tip-sample distance and limit the achievable accuracy on the bond length determination based on AFM experiments.
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Affiliation(s)
- Mark P Boneschanscher
- Debye Institute for Nanomaterials Science, Utrecht University , P.O. Box 80000, 3508TA Utrecht, The Netherlands
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40
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Hofmann T, Pielmeier F, Giessibl FJ. Chemical and crystallographic characterization of the tip apex in scanning probe microscopy. PHYSICAL REVIEW LETTERS 2014; 112:066101. [PMID: 24580694 DOI: 10.1103/physrevlett.112.066101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Indexed: 06/03/2023]
Abstract
The apex atom of a W scanning probe tip reveals a nonspherical charge distribution as probed by a CO molecule bonded to a Cu(111) surface [Welker et al., Science 336, 444 (2012). Three high-symmetry images were observed and related to three low-index crystallographic directions of the W bcc crystal. Open questions remained, such as the detectability of a contamination of W tips by sample material (here Cu), and the applicability of the method to distinguish other atomic species. In this work, we investigate bulk Cu and Fe tips. In both cases, we can associate our data with the fcc (Cu) and bcc (Fe) crystal structures using a simple electrostatic model that is based on the partial filling of d orbitals.
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Affiliation(s)
- Thomas Hofmann
- Institute of Experimental and Applied Physics, University of Regensburg, D-93053 Regensburg, Germany
| | - Florian Pielmeier
- Institute of Experimental and Applied Physics, University of Regensburg, D-93053 Regensburg, Germany
| | - Franz J Giessibl
- Institute of Experimental and Applied Physics, University of Regensburg, D-93053 Regensburg, Germany
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41
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Weymouth AJ, Hofmann T, Giessibl FJ. Quantifying molecular stiffness and interaction with lateral force microscopy. Science 2014; 343:1120-2. [PMID: 24505131 DOI: 10.1126/science.1249502] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The spatial resolution of atomic force microscopy (AFM) can be drastically increased by terminating the tip with a single carbon monoxide (CO) molecule. However, the CO molecule is not stiff, and lateral forces, such as those around the sides of molecules, distort images. This issue begs a larger question of how AFM can probe structures that are laterally weak. Lateral force microscopy (LFM) can probe lateral stiffnesses that are not accessible to normal-force AFM, resulting in higher spatial resolution. With LFM, we determined the torsional spring constant of a CO-terminated tip molecule to be 0.24 newtons per meter. This value is less than that of a surface molecule and an example of a system whose stiffness is a product not only of bonding partners but also local environment.
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42
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Dedkov Y, Voloshina E. Multichannel scanning probe microscopy and spectroscopy of graphene moiré structures. Phys Chem Chem Phys 2014; 16:3894-908. [DOI: 10.1039/c3cp54541e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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43
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van der Lit J, Boneschanscher MP, Vanmaekelbergh D, Ijäs M, Uppstu A, Ervasti M, Harju A, Liljeroth P, Swart I. Suppression of electron-vibron coupling in graphene nanoribbons contacted via a single atom. Nat Commun 2013; 4:2023. [PMID: 23756598 DOI: 10.1038/ncomms3023] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 05/17/2013] [Indexed: 01/22/2023] Open
Abstract
Graphene nanostructures, where quantum confinement opens an energy gap in the band structure, hold promise for future electronic devices. To realize the full potential of these materials, atomic-scale control over the contacts to graphene and the graphene nanostructure forming the active part of the device is required. The contacts should have a high transmission and yet not modify the electronic properties of the active region significantly to maintain the potentially exciting physics offered by the nanoscale honeycomb lattice. Here we show how contacting an atomically well-defined graphene nanoribbon to a metallic lead by a chemical bond via only one atom significantly influences the charge transport through the graphene nanoribbon but does not affect its electronic structure. Specifically, we find that creating well-defined contacts can suppress inelastic transport channels.
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Affiliation(s)
- Joost van der Lit
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands
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Majzik Z, Rachid Tchalala M, Svec M, Hapala P, Enriquez H, Kara A, Mayne AJ, Dujardin G, Jelínek P, Oughaddou H. Combined AFM and STM measurements of a silicene sheet grown on the Ag(111) surface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:225301. [PMID: 23674193 DOI: 10.1088/0953-8984/25/22/225301] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this paper, we present the first non-contact atomic force microscopy (nc-AFM) of a silicene on a silver (Ag) surface, obtained by combining non-contact atomic force microscopy and scanning tunneling microscopy (STM). STM images over large areas of silicene grown on the Ag(111) surface show both (√13 × √13)R13.9° and (4 × 4) superstructures. For the widely observed (4 × 4) structure, the observed nc-AFM image is very similar to the one recorded by STM. The structure resolved by nc-AFM is compatible with only one out of two silicon atoms being visible. This indicates unambiguously a strong buckling of the silicene honeycomb layer.
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Affiliation(s)
- Z Majzik
- Insitute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, Praha, 16200, Czech Republic.
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Voloshina EN, Fertitta E, Garhofer A, Mittendorfer F, Fonin M, Thissen A, Dedkov YS. Electronic structure and imaging contrast of graphene moiré on metals. Sci Rep 2013; 3:1072. [PMID: 23330062 PMCID: PMC3547320 DOI: 10.1038/srep01072] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 01/03/2013] [Indexed: 11/24/2022] Open
Abstract
Realization of graphene moiré superstructures on the surface of 4d and 5d transition metals offers templates with periodically modulated electron density, which is responsible for a number of fascinating effects, including the formation of quantum dots and the site selective adsorption of organic molecules or metal clusters on graphene. Here, applying the combination of scanning probe microscopy/spectroscopy and the density functional theory calculations, we gain a profound insight into the electronic and topographic contributions to the imaging contrast of the epitaxial graphene/Ir(111) system. We show directly that in STM imaging the electronic contribution is prevailing compared to the topographic one. In the force microscopy and spectroscopy experiments we observe a variation of the interaction strength between the tip and high-symmetry places within the graphene moiré supercell, which determine the adsorption sites for molecules or metal clusters on graphene/Ir(111).
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Affiliation(s)
- E N Voloshina
- Physikalische und Theoretische Chemie, Freie Universität Berlin, 14195 Berlin, Germany
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