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Brand C, Hucht A, Jnawali G, Fortmann JD, Sothmann B, Mehdipour H, Kratzer P, Schützhold R, Horn-von Hoegen M. Dimer Coupling Energies of the Si(001) Surface. PHYSICAL REVIEW LETTERS 2023; 130:126203. [PMID: 37027849 DOI: 10.1103/physrevlett.130.126203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 02/02/2023] [Indexed: 06/19/2023]
Abstract
The coupling energies between the buckled dimers of the Si(001) surface were determined through analysis of the anisotropic critical behavior of its order-disorder phase transition. Spot profiles in high-resolution low-energy electron diffraction as a function of temperature were analyzed within the framework of the anisotropic two-dimensional Ising model. The validity of this approach is justified by the large ratio of correlation lengths, ξ_{∥}^{+}/ξ_{⊥}^{+}=5.2 of the fluctuating c(4×2) domains above the critical temperature T_{c}=(190.6±10) K. We obtain effective couplings J_{∥}=(-24.9±1.3) meV along the dimer rows and J_{⊥}=(-0.8±0.1) meV across the dimer rows, i.e., antiferromagneticlike coupling of the dimers with c(4×2) symmetry.
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Affiliation(s)
- Christian Brand
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Alfred Hucht
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
- Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Giriraj Jnawali
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Jonas D Fortmann
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Björn Sothmann
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
- Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Hamid Mehdipour
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Peter Kratzer
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
- Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
| | - Ralf Schützhold
- Institute of Theoretical Physics, Dresden University of Technology, 01062 Dresden, Germany
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - Michael Horn-von Hoegen
- Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany
- Center for Nanointegration (CENIDE), University of Duisburg-Essen, 47057 Duisburg, Germany
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Lu F, Li JX, Guo WX, Wang BL, Zhang YQ. Origin of Magnetic Relaxation Barriers in a Family of Cobalt(II)-Radical Single-Chain Magnets: Density Functional Theory and Ab Initio Calculations. Inorg Chem 2021; 60:1007-1015. [PMID: 33410671 DOI: 10.1021/acs.inorgchem.0c03115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Density functional theory (DFT) and ab initio calculations were performed to probe the origin of the magnetic relaxation barriers for two finite single-chain magnets (SCMs) featuring a one-dimension chain, Co(hfac)2(R-NapNIT) (R-NapNIT = 2-(2'-(R-)naphthyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, R = MeO (1) or EtO (2)). Our calculations show that the strong intrachain CoII-CoII exchange coupling interactions transmitted by radicals can contribute much more than ionic anisotropy to the height of the reversal barrier of magnetization for the single-chain magnets (SCMs) with |2E| < |4J/3|. In addition, the anisotropic energy barrier ΔA decreases with the decrease of |2E/J| ratio and finally vanishes in the limit of broad domain walls (|2E| < < |4 J/3|). Therefore, the total magnetic relaxation energy barriers of two SCMs mostly originate from the correlation energy barrier Δξ deriving from the indirect ferromagnetic interaction between CoII-CoII transmitted by the strong CoII-radical antiferromagnetic interactions.
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Affiliation(s)
- Fang Lu
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Jia-Xin Li
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Wen-Xiao Guo
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Bao-Lin Wang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Yi-Quan Zhang
- Jiangsu Key Lab for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, P. R. China
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Gordon OM, Moriarty PJ. Machine learning at the (sub)atomic scale: next generation scanning probe microscopy. MACHINE LEARNING-SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1088/2632-2153/ab7d2f] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Yengui M, Duverger E, Sonnet P, Riedel D. A two-dimensional ON/OFF switching device based on anisotropic interactions of atomic quantum dots on Si(100):H. Nat Commun 2017; 8:2211. [PMID: 29263380 PMCID: PMC5738427 DOI: 10.1038/s41467-017-02377-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/23/2017] [Indexed: 11/09/2022] Open
Abstract
Controlling the properties of quantum dots at the atomic scale, such as dangling bonds, is a general motivation as they allow studying various nanoscale processes including atomic switches, charge storage, or low binding energy state interactions. Adjusting the coupling of individual silicon dangling bonds to form a 2D device having a defined function remains a challenge. Here, we exploit the anisotropic interactions between silicon dangling bonds on n-type doped Si(100):H surface to tune their hybridization. This process arises from interactions between the subsurface silicon network and dangling bonds inducing a combination of Jahn-Teller distortions and local charge ordering. A three-pointed star-shaped device prototype is designed. By changing the charge state of this device, its electronic properties are shown to switch reversibly from an ON to an OFF state via local change of its central gap. Our results provide a playground for the study of quantum information at the nanoscale.
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Affiliation(s)
- Mayssa Yengui
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Eric Duverger
- Institut FEMTO-ST, Univ. Bourgogne Franche-Comté, CNRS, 15B avenue des Montboucons, 25030, Besançon, France
| | - Philippe Sonnet
- Institut de Science des Matériaux de Mulhouse (IS2M), CNRS, UMR 7361, Université de Haute Alsace, 3 bis rue Alfred Werner, 68057, Mulhouse, France
| | - Damien Riedel
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris Sud, Université Paris-Saclay, 91405, Orsay, France.
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Wortmann B, van Vörden D, Graf P, Robles R, Abufager P, Lorente N, Bobisch CA, Möller R. Reversible 2D Phase Transition Driven By an Electric Field: Visualization and Control on the Atomic Scale. NANO LETTERS 2016; 16:528-533. [PMID: 26645498 DOI: 10.1021/acs.nanolett.5b04174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on a reversible structural phase transition of a two-dimensional system that can be locally induced by an external electric field. Two different structural configurations may coexist within a CO monolayer on Cu(111). The balance between the two phases can be shifted by an external electric field, causing the domain boundaries to move, increasing the area of the favored phase controllable both in location and size. If the field is further enhanced new domains nucleate. The arrangement of the CO molecules on the Cu surface is observed in real time and real space with atomic resolution while the electric field driving the phase transition is easily varied over a broad range. Together with the well-known molecular manipulation of CO adlayers, our findings open exciting prospects for combining spontaneous long-range order with man-made CO structures such as "molecule cascades" or "molecular graphene". Our new manipulation mode permits us to bridge the gap between fundamental concepts and the fabrication of arbitrary atomic patterns in large scale, by providing unprecedented insight into the physics of structural phase transitions on the atomic scale.
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Affiliation(s)
- B Wortmann
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen , Lotharstraße1-21, 47048 Duisburg, Germany
| | - D van Vörden
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen , Lotharstraße1-21, 47048 Duisburg, Germany
| | - P Graf
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen , Lotharstraße1-21, 47048 Duisburg, Germany
| | - R Robles
- ICN2 Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - P Abufager
- ICN2 Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Instituto de Física de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and Universidad Nacional de Rosario, Avenidas Pellegrini 250, 2000 Rosario, Santa Fe, Argentina
| | - N Lorente
- ICN2 Catalan Institute of Nanoscience and Nanotechnology, CSIC and The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Centro de Física de Materiales, CFM/MPC (CSIC-UPV/EHU) , Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
- Donostia International Physics Center (DIPC) , Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
| | - C A Bobisch
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen , Lotharstraße1-21, 47048 Duisburg, Germany
| | - R Möller
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen , Lotharstraße1-21, 47048 Duisburg, Germany
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Dissociative adsorption of CH3X (X = Br and Cl) on a silicon(100) surface revisited by density functional theory. J Chem Phys 2014; 141:174701. [DOI: 10.1063/1.4899841] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Schaffert J, Cottin MC, Sonntag A, Karacuban H, Utzat D, Bobisch CA, Möller R. Scanning noise microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:043702. [PMID: 23635198 DOI: 10.1063/1.4801458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The paper describes a simple scheme enabling the real-time characterization of fluctuations, e.g., of the conductance in scanning tunneling microscopy. The technique can be used in parallel to other data acquisition, evaluating the rate, the amplitude, and the duty cycle of telegraphic noise in the tunneling current. This kind of scanning probe microscopy allows to evaluate the noise parameters as a function of the average tunneling current, the electron energy, and the lateral position. Images of the noise with Ångstrom spatial resolution are acquired simultaneously to the topographic information providing a direct correlation between the structural information and the noise. The method can be applied to a large variety of systems to monitor dynamics on the nanoscale, e.g., the localization of tunneling current induced switching within a single molecule. Noise spectroscopy may reveal the involved molecular orbitals, even if they cannot be resolved in standard scanning tunneling spectroscopy. As an example we present experimental data of the organic molecule copper phthalocyanine on a Cu(111) surface [J. Schaffert, M. C. Cottin, A. Sonntag, H. Karacuban, C. A. Bobisch, N. Lorente, J.-P. Gauyacq, and R. Möller, Nature Mater. 12, 223-227 (2013)].
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Affiliation(s)
- J Schaffert
- Faculty of Physics, University of Duisburg-Essen, Center for Nanointegration Duisburg-Essen (CENIDE), 47048 Duisburg, Germany
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Kim TH, Yeom HW. Topological solitons versus nonsolitonic phase defects in a quasi-one-dimensional charge-density wave. PHYSICAL REVIEW LETTERS 2012; 109:246802. [PMID: 23368361 DOI: 10.1103/physrevlett.109.246802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Indexed: 06/01/2023]
Abstract
We investigated phase defects in a quasi-one-dimensional commensurate charge-density wave (CDW) system, an In atomic wire array on Si(111), using low temperature scanning tunneling microscopy. The unique fourfold degeneracy of the CDW state leads to various phase defects, among which intrinsic solitons are clearly distinguished. The solitons exhibit a characteristic variation of the CDW amplitude with a coherence length of about 4 nm, as expected from the electronic structure, and a localized electronic state within the CDW gap. While most of the observed solitons are trapped by extrinsic defects, moving solitons are also identified and their novel interaction with extrinsic defects is disclosed.
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Affiliation(s)
- Tae-Hwan Kim
- Center for Low Dimensional Electronic Symmetry and Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea.
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Sweetman A, Danza R, Gangopadhyay S, Moriarty P. Imaging and manipulation of the Si(100) surface by small-amplitude NC-AFM at zero and very low applied bias. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:084009. [PMID: 22310449 DOI: 10.1088/0953-8984/24/8/084009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We use a noncontact atomic force microscope in the qPlus configuration to investigate the structure and influence of defects on the Si(100) surface. By applying millivolt biases, simultaneous tunnel current data is acquired, providing information about the electronic properties of the surface at biases often inaccessible during conventional STM imaging, and highlighting the difference between the contrast observed in NC-AFM and tunnel current images. We also show how NC-AFM (in the absence of tunnel current) can be used to manipulate both the clean c(4 × 2) surface and dopant-related defects.
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Affiliation(s)
- A Sweetman
- School of Physics and Astronomy, University of Nottingham, Nottingham, UK.
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Jung W, Cho D, Kim MK, Choi HJ, Lyo IW. Time-resolved energy transduction in a quantum capacitor. Proc Natl Acad Sci U S A 2011; 108:13973-7. [PMID: 21817067 PMCID: PMC3161544 DOI: 10.1073/pnas.1102474108] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The capability to deposit charge and energy quantum-by-quantum into a specific atomic site could lead to many previously unidentified applications. Here we report on the quantum capacitor formed by a strongly localized field possessing such capability. We investigated the charging dynamics of such a capacitor by using the unique scanning tunneling microscopy that combines nanosecond temporal and subangstrom spatial resolutions, and by using Si(001) as the electrode as well as the detector for excitations produced by the charging transitions. We show that sudden switching of a localized field induces a transiently empty quantum dot at the surface and that the dot acts as a tunable excitation source with subangstrom site selectivity. The timescale in the deexcitation of the dot suggests the formation of long-lived, excited states. Our study illustrates that a quantum capacitor has serious implications not only for the bottom-up nanotechnology but also for future switching devices.
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Affiliation(s)
- Woojin Jung
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Doohee Cho
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Min-Kook Kim
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - Hyoung Joon Choi
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
| | - In-Whan Lyo
- Department of Physics, and Institute of Physics and Applied Physics, Yonsei University, Seoul 120-749, Korea
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11
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Sweetman A, Jarvis S, Danza R, Bamidele J, Gangopadhyay S, Shaw GA, Kantorovich L, Moriarty P. Toggling bistable atoms via mechanical switching of bond angle. PHYSICAL REVIEW LETTERS 2011; 106:136101. [PMID: 21517399 DOI: 10.1103/physrevlett.106.136101] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Indexed: 05/22/2023]
Abstract
We reversibly switch the state of a bistable atom by direct mechanical manipulation of bond angle using a dynamic force microscope. Individual buckled dimers at the Si(100) surface are flipped via the formation of a single covalent bond, actuating the smallest conceivable in-plane toggle switch (two atoms) via chemical force alone. The response of a given dimer to a flip event depends critically on both the local and nonlocal environment of the target atom-an important consideration for future atomic scale fabrication strategies.
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Affiliation(s)
- Adam Sweetman
- The School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
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12
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van Houselt A, Poelsema B, Zandvliet HJW. Atomic seesaws. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:264004. [PMID: 21386461 DOI: 10.1088/0953-8984/22/26/264004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The dynamics of two types of atomic seesaws are studied by open feedback loop scanning tunneling microscopy. The first type of atomic seesaw is a regular Ge dimer of the dimer reconstructed Ge(001) surface and the second type of atomic seesaw is a dimer located on the ridges of Au induced nanowires on a Ge(001) surface. On the bare Ge(001) surface the flip-flop motion of the dimers is induced by phasons, which perform a one-dimensional random walk along the substrate dimer rows. The phasons on the Au induced nanowires ridges are pinned and therefore only a limited number of dimers exhibit flip-flop behavior for the Au/Ge(001) system.
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Affiliation(s)
- Arie van Houselt
- Physical Aspects of Nanoelectronics, MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
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Riedel D. Single molecule manipulation at low temperature and laser scanning tunnelling photo-induced processes analysis through time-resolved studies. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:264009. [PMID: 21386466 DOI: 10.1088/0953-8984/22/26/264009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper describes, firstly, the statistical analysis used to determine the processes that occur during the manipulation of a single molecule through electronically induced excitations with a low temperature (5 K) scanning tunnelling microscope (STM). Various molecular operation examples are described and the ability to probe the ensuing molecular manipulation dynamics is discussed within the excitation context. It is, in particular, shown that such studies can reveal reversible manipulation for tuning dynamics through variation of the excitation energy. Secondly, the photo-induced process arising from the irradiation of the STM junction is also studied through feedback loop dynamics analysis, allowing us to distinguish between photo-thermally and photo-electronically induced signals.
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Affiliation(s)
- Damien Riedel
- Institut des Sciences Moléculaires d'Orsay, ISMO, CNRS, Bâtiment 210, Université Paris Sud, 91405 Orsay, France.
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Zandvliet HJW, van Houselt A. Scanning tunneling spectroscopy. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2009; 2:37-55. [PMID: 20636053 DOI: 10.1146/annurev-anchem-060908-155213] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The scanning tunneling microscope (STM) has revolutionized our ability to explore and manipulate atomic-scale solid surfaces. In addition to its unparalleled spatial power, the STM can study dynamical processes, such as molecular conformational changes, by recording current traces as a function of time. It can also be employed to measure the physical properties of molecules or nanostructures down to the atomic scale. Combining STM imaging with measurement of current-voltage (I-V) characteristics [i.e., scanning tunneling spectroscopy (STS)] at similar resolution makes it possible to obtain a detailed map of the electronic structure of a surface. For many years, STM lacked chemical specificity; however, the recent development of STM-IETS (inelastic electron tunneling spectroscopy) has allowed us to measure the vibrational spectrum of a single molecule. This review introduces and illustrates these recent developments with a few simple scholarly examples.
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Affiliation(s)
- Harold J W Zandvliet
- Physical Aspects of Nanoelectronics and the MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
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van Houselt A, van Gastel R, Poelsema B, Zandvliet HJW. Dynamics and energetics of Ge(001) dimers. PHYSICAL REVIEW LETTERS 2006; 97:266104. [PMID: 17280433 DOI: 10.1103/physrevlett.97.266104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Indexed: 05/13/2023]
Abstract
The dynamic behavior of surface dimers on Ge(001) has been studied by positioning the tip of a scanning tunneling microscope over single flip-flopping dimers and measuring the tunneling current as a function of time. We observe that not just symmetric, but also asymmetric appearing dimers exhibit flip-flop motion. The dynamics of flip-flopping dimers can be used to sensitively gauge the local potential landscape of the surface. Through a spatial and time-resolved measurement of the flip-flop frequency of the dimers, local strain fields near surface defects can be accurately probed.
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Affiliation(s)
- Arie van Houselt
- Physical Aspects of Nanoelectronics and Solid State Physics, MESA(+) Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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