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Ismael AK, Rincón-García L, Evangeli C, Dallas P, Alotaibi T, Al-Jobory AA, Rubio-Bollinger G, Porfyrakis K, Agraït N, Lambert CJ. Exploring seebeck-coefficient fluctuations in endohedral-fullerene, single-molecule junctions. NANOSCALE HORIZONS 2022; 7:616-625. [PMID: 35439804 DOI: 10.1039/d1nh00527h] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
For the purpose of creating single-molecule junctions, which can convert a temperature difference ΔT into a voltage ΔV via the Seebeck effect, it is of interest to screen molecules for their potential to deliver high values of the Seebeck coefficient S = -ΔV/ΔT. Here we demonstrate that insight into molecular-scale thermoelectricity can be obtained by examining the widths and extreme values of Seebeck histograms. Using a combination of experimental scanning-tunnelling-microscopy-based transport measurements and density-functional-theory-based transport calculations, we study the electrical conductance and Seebeck coefficient of three endohedral metallofullerenes (EMFs) Sc3N@C80, Sc3C2@C80, and Er3N@C80, which based on their structures, are selected to exhibit different degrees of charge inhomogeneity and geometrical disorder within a junction. We demonstrate that standard deviations in the Seebeck coefficient σS of EMF-based junctions are correlated with the geometric standard deviation σ and the charge inhomogeneity σq. We benchmark these molecules against C60 and demonstrate that both σq, σS are the largest for Sc3C2@C80, both are the smallest for C60 and for the other EMFs, they follow the order Sc3C2@C80 > Sc3N@C80 > Er3N@C80 > C60. A large value of σS is a sign that a molecule can exhibit a wide range of Seebeck coefficients, which means that if orientations corresponding to high values can be selected and controlled, then the molecule has the potential to exhibit high-performance thermoelectricity. For the EMFs studied here, large values of σS are associated with distributions of Seebeck coefficients containing both positive and negative signs, which reveals that all these EMFs are bi-thermoelectric materials.
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Affiliation(s)
- Ali K Ismael
- Department of Physics, Lancaster University, Lancaster, UK.
- Department of Physics, College of Education for Pure Science, Tikrit University, Tikrit, Iraq
| | - Laura Rincón-García
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | | | - Panagiotis Dallas
- Institute of Nanoscience and Nanotechnology, NCSR Demokritos, 15310 Athens, Greece
- Department of Materials, University of Oxford, OX1 3PH, UK
| | - Turki Alotaibi
- Department of Physics, Lancaster University, Lancaster, UK.
- Department of Physics, College of Science, Jouf University, Sakaka, Saudi Arabia
| | - Alaa A Al-Jobory
- Department of Physics, Lancaster University, Lancaster, UK.
- Department of Physics, College of Science, University of Anbar, Anbar, Iraq
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Kyriakos Porfyrakis
- Department of Materials, University of Oxford, OX1 3PH, UK
- Faculty of Engineering and Science, University of Greenwich, Central Avenue, Chatham Maritime, ME4 4TB, UK
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC) and Instituto Universitario de Ciencia de Materiales "Nicolás Cabrera" (INC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, E-28049 Madrid, Spain
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2
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Sato T, Milne ZB, Nomura M, Sasaki N, Carpick RW, Fujita H. Ultrahigh strength and shear-assisted separation of sliding nanocontacts studied in situ. Nat Commun 2022; 13:2551. [PMID: 35538085 PMCID: PMC9091249 DOI: 10.1038/s41467-022-30290-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 04/12/2022] [Indexed: 11/27/2022] Open
Abstract
The behavior of materials in sliding contact is challenging to determine since the interface is normally hidden from view. Using a custom microfabricated device, we conduct in situ, ultrahigh vacuum transmission electron microscope measurements of crystalline silver nanocontacts under combined tension and shear, permitting simultaneous observation of contact forces and contact width. While silver classically exhibits substantial sliding-induced plastic junction growth, the nanocontacts exhibit only limited plastic deformation despite high applied stresses. This difference arises from the nanocontacts’ high strength, as we find the von Mises stresses at yield points approach the ideal strength of silver. We attribute this to the nanocontacts’ nearly defect-free nature and small size. The contacts also separate unstably, with pull-off forces well below classical predictions for rupture under pure tension. This strongly indicates that shearing reduces nanoscale pull-off forces, predicted theoretically at the continuum level, but not directly observed before. To understand and predict friction, it is crucial to observe sliding at the nanoscale to uncover the mechanisms at play. Here, the authors show that nano-contacts exhibit strength near the ideal limit, and find that pull-off forces predicted by continuum models are reduced by shearing.
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Affiliation(s)
- Takaaki Sato
- University of Pennsylvania, Department of Mechanical Engineering and Applied Mechanics, Philadelphia, PA, USA.
| | - Zachary B Milne
- Sandia National Laboratories, Nanostructure Physics, Albuquerque, NM, USA
| | - Masahiro Nomura
- University of Tokyo, Institute of Industrial Science, Tokyo, JP, Japan
| | - Naruo Sasaki
- The University of Electro-Communications, Department of Engineering Science, Tokyo, JP, Japan
| | - Robert W Carpick
- University of Pennsylvania, Department of Mechanical Engineering and Applied Mechanics, Philadelphia, PA, USA
| | - Hiroyuki Fujita
- University of Tokyo, Institute of Industrial Science, Tokyo, JP, Japan.,Tokyo city university, Graduate school of integrative science and engineering electrical and electronic engineering, Tokyo, JP, Japan
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3
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Khosravi A, Lainé A, Vanossi A, Wang J, Siria A, Tosatti E. Understanding the rheology of nanocontacts. Nat Commun 2022; 13:2428. [PMID: 35508482 PMCID: PMC9068906 DOI: 10.1038/s41467-022-30096-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 04/13/2022] [Indexed: 11/09/2022] Open
Abstract
Mechanical stiffness, as opposed to softness, is a fundamental property of solids. Its persistence or rheological evolution in vibrating solid-solid nanocontacts is important in physics, materials science and technology. A puzzling apparent liquefaction under oscillatory strain, totally unexpected at room temperature, was suggested by recent experiments on solid gold nano-junctions. Here we show theoretically that realistically simulated nanocontacts actually remain crystalline even under large oscillatory strains. Tensile and compressive slips, respectively of “necking” and “bellying” types, do take place, but recover reversibly even during fast oscillatory cycles. We also show that, counterintuitively, the residual stress remains tensile after both slips, driving the averaged stiffness from positive to negative, thus superficially mimicking a liquid’s. Unlike a liquid, however, rheological softening occurs by stick-slip, predicting largely frequency independent stiffness with violent noise in stress and conductance, properties compatible with experiments. The baffling large amplitude rheology of gold nanocontacts and its consequences should apply, with different parameters, to many other metals. The rigidity of solid nanocontacts formed when metals touch is apparently lost liquidlike under large mechanical oscillations. As we show theoretically, there is no melting but oscillated nanocontacts undergo a remarkable reversible stick-slip rheology.
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Affiliation(s)
- Ali Khosravi
- International School for Advanced Studies (SISSA), I-34136, Trieste, Italy.,International Centre for Theoretical Physics, I-34151, Trieste, Italy.,CNR-IOM, Consiglio Nazionale delle Ricerche - Istituto Officina dei Materiali, c/o SISSA, 34136, Trieste, Italy
| | - Antoine Lainé
- Laboratoire de Physique de lÉcole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université Universitté Paris-Diderot, Sorbonne Paris Cité, UMR CNRS 8550, Paris, France
| | - Andrea Vanossi
- International School for Advanced Studies (SISSA), I-34136, Trieste, Italy.,CNR-IOM, Consiglio Nazionale delle Ricerche - Istituto Officina dei Materiali, c/o SISSA, 34136, Trieste, Italy
| | - Jin Wang
- International School for Advanced Studies (SISSA), I-34136, Trieste, Italy
| | - Alessandro Siria
- Laboratoire de Physique de lÉcole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université Universitté Paris-Diderot, Sorbonne Paris Cité, UMR CNRS 8550, Paris, France
| | - Erio Tosatti
- International School for Advanced Studies (SISSA), I-34136, Trieste, Italy. .,International Centre for Theoretical Physics, I-34151, Trieste, Italy. .,CNR-IOM, Consiglio Nazionale delle Ricerche - Istituto Officina dei Materiali, c/o SISSA, 34136, Trieste, Italy.
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4
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Li J, Kasal B. Effects of Thermal Aging on the Adhesion Forces of Biopolymers of Wood Cell Walls. Biomacromolecules 2022; 23:1601-1609. [PMID: 35303409 PMCID: PMC9006222 DOI: 10.1021/acs.biomac.1c01397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Wood is the most important, industrially used renewable resource on the planet, but the aging mechanism of biopolymers on cell walls is poorly understood. Adhesion properties are of critical importance for wood and many other lignocellulosic materials. We used atomic force microscopy and defined the jump-off force ratio in the retract force-displacement curve to study the adhesion force phenomenon and the effects of heat treatments. Here, we identified two sigmoidal curves describing the shift of the adhesion force and the jump-off force ratio: the first curve was attributed to the movement of extractives and the second to the degradation of the hemicellulose-lignin matrix. We confirmed the hypothesis formulated in this paper by the cell wall surface topography, the analysis of the treated samples by Fourier transform infrared spectroscopy, and the analysis of volatiles during heating by headspace gas chromatography-mass spectrometry.
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Affiliation(s)
- Juan Li
- Division of Organic and Wood-Based Materials, TU Braunschweig, Hopfengarten 20, 38102 Braunschweig, Germany
| | - Bohumil Kasal
- Division of Organic and Wood-Based Materials, TU Braunschweig, Hopfengarten 20, 38102 Braunschweig, Germany.,Fraunhofer Wilhelm-Klauditz-Institut WKI, Bienroder Weg 54E, 38108 Braunschweig, Germany
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5
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Tsuruoka Y, Obi T, Kizuka T. Reversible phase-transition control in nanometer-sized zirconium wires via pulse-voltage impression. NANO EXPRESS 2020. [DOI: 10.1088/2632-959x/ab951e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
Pulse-voltage-stimulated phase transition in nanometer-sized zirconium (Zr) wires was observed in situ by high-resolution transmission electron microscopy. Simultaneously, the variation in conductance during the transition between crystalline and amorphous phases was examined. The crystalline phase of a hexagonal closed-packed structure in the wires transformed into an amorphous phase while applying pulse voltages of 4 ns in width, and subsequently returned to the initial crystalline phase by the impression of pulse voltages of 5 ms in width; the reversible phase transition via voltage impression using shorter and longer pulse waves was observed. The average conductance per a unit area in the amorphous phases was decreased to 0.87 of the crystalline phases. The amorphous region in the wires expanded gradually by every pulse-voltage impression, whereas the conductance decreased stepwise in response to the gradual expansion. It was demonstrated that the conductance of the wires can be controlled in a stepwise manner via pulse-voltage impression, leading to the application of the nanowires to functional nanodevices.
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6
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Cui Y, Ju Y, Meguid SA. Atomistic treatment of periodic gold nanowire array nanofasteners under shear loading. NANOTECHNOLOGY 2019; 31:105704. [PMID: 31751968 DOI: 10.1088/1361-6528/ab5a0a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Comprehensive molecular dynamics simulations are conducted to unravel the mechanics and mechanisms associated with the strength and fracture behavior of a highly ordered gold nanowire (Au-NW) array of a pair of nanofasteners (nanoconnectors) under externally applied shear strain. Large-scale atomic/molecular massively parallel simulator (LAMMPS and embedded atom method were adopted to model the atomic interactions of a number of neighboring nanofasteners. This was affected via the use of a periodic simulation box around a pair of highly ordered nanotube arrays to minimize the cost of the computations. Energy minimization using a conjugate gradient algorithm was first performed and followed by atomic relaxation to achieve an equilibrated configuration under the canonical ensemble of constant temperature and volume. The relaxed equilibrated configuration of the nanofastener was then subjected to an externally applied shear strain [Formula: see text] at a rate of [Formula: see text] per nanosecond under the canonical ensemble. Our results reveal the importance of the morphology and the overlap depth of the mating nanowire arrays upon the mechanical and fracture behavior of the nanofastener under shear loading. Our work also disclosed the phenomenon of multiple contacts of some displaced nanowires with their neighbors even after their fracture leading to multiple cold-welds with added redundancy to the nanofastener. Finally, in this research, we identified the locations of dislocation emissions and the resulting fracture processes that govern the mechanical integrity and ultimately the functionality of the Au-NW connector. The proposed highly ordered alignment, as conceived numerically herein, can yield a peak stress two to three times higher than that corresponding to a random alignment reported in a previous study. The Au-NW connector also exhibited resistance to fracture, even in cases where small overlap depth is considered in joint bonding. The nanoconnector was also tested at high temperatures (up to 450 K). Our results show that the rising temperature only leads to a minor reduction in the load transmitted by the nanoconnector.
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Affiliation(s)
- Yi Cui
- Department of Micro-Nano Mechanical Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan
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7
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Abstract
The study of biological samples is one of the most attractive and innovative fields of application of atomic force microscopy AFM. Recent breakthroughs in software and hardware have revolutionized this field and this paper reports on recent trends and describes examples of applications on biological samples. Originally developed for high-resolution imaging purposes, the AFM also has unique capabilities as a nano-indentor to probe the dynamic visco-elastic material properties of living cells in culture. In particular, AFM elastography combines imaging and indentation modalities to map the spatial distribution of cell mechanical properties, which in turn reflect the structure and function of the underlying structure. This paper describes the progress and development of atomic force microscopy as applied to animal and plant cell structures.
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8
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Seo MH, Ko JH, Lee JO, Ko SD, Mun JH, Cho BJ, Kim YH, Yoon JB. >1000-Fold Lifetime Extension of a Nickel Electromechanical Contact Device via Graphene. ACS APPLIED MATERIALS & INTERFACES 2018; 10:9085-9093. [PMID: 29461033 DOI: 10.1021/acsami.7b15772] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Micro-/nano-electromechanical (M/NEM) switches have received significant attention as promising switching devices for a wide range of applications such as computing, radio frequency communication, and power gating devices. However, M/NEM switches still suffer from unacceptably low reliability because of irreversible degradation at the contacting interfaces, hindering adoption in practical applications and further development. Here, we evaluate and verify graphene as a contact material for reliability-enhanced M/NEM switching devices. Atomic force microscopy experiments and quantum mechanics calculations reveal that energy-efficient mechanical contact-separation characteristics are achieved when a few layers of graphene are used as a contact material on a nickel surface, reducing the energy dissipation by 96.6% relative to that of a bare nickel surface. Importantly, graphene displays almost elastic contact-separation, indicating that little atomic-scale wear, including plastic deformation, fracture, and atomic attrition, is generated. We also develop a feasible fabrication method to demonstrate a MEM switch, which has high-quality graphene as the contact material, and verify that the devices with graphene show mechanically stable and elastic-like contact properties, consistent with our nanoscale contact experiment. The graphene coating extends the switch lifetime >103 times under hot switching conditions.
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9
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Lauritzen KP, Magyarkuti A, Balogh Z, Halbritter A, Solomon GC. Classification of conductance traces with recurrent neural networks. J Chem Phys 2018; 148:084111. [PMID: 29495782 DOI: 10.1063/1.5012514] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a new automated method for structural classification of the traces obtained in break junction experiments. Using recurrent neural networks trained on the traces of minimal cross-sectional area in molecular dynamics simulations, we successfully separate the traces into two classes: point contact or nanowire. This is done without any assumptions about the expected features of each class. The trained neural network is applied to experimental break junction conductance traces, and it separates the classes as well as the previously used experimental methods. The effect of using partial conductance traces is explored, and we show that the method performs equally well using full or partial traces (as long as the trace just prior to breaking is included). When only the initial part of the trace is included, the results are still better than random chance. Finally, we show that the neural network classification method can be used to classify experimental conductance traces without using simulated results for training, but instead training the network on a few representative experimental traces. This offers a tool to recognize some characteristic motifs of the traces, which can be hard to find by simple data selection algorithms.
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Affiliation(s)
- Kasper P Lauritzen
- Nano-Science Center and Department of Chemistry, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - András Magyarkuti
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - Zoltán Balogh
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - András Halbritter
- Department of Physics, Budapest University of Technology and Economics and MTA-BME Condensed Matter Research Group, Budafoki ut 8, 1111 Budapest, Hungary
| | - Gemma C Solomon
- Nano-Science Center and Department of Chemistry, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
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10
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Yamada K, Kizuka T. Transformation from slip to plastic flow deformation mechanism during tensile deformation of zirconium nanocontacts. Sci Rep 2017; 7:42901. [PMID: 28218244 PMCID: PMC5317169 DOI: 10.1038/srep42901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 01/17/2017] [Indexed: 11/30/2022] Open
Abstract
Various types of nanometer-sized structures have been applied to advanced functional and structural devices. Inherent structures, thermal stability, and properties of such nanostructures are emphasized when their size is decreased to several nanometers, especially, to several atoms. In this study, we observed the atomistic tensile deformation process of zirconium nanocontacts, which are typical nanostructures used in connection of nanometer-sized wires, transistors, and diodes, memory devices, and sensors, by in situ transmission electron microscopy. It was found that the contact was deformed via a plastic flow mechanism, which differs from the slip on lattice planes frequently observed in metals, and that the crystallinity became disordered. The various irregular relaxed structures formed during the deformation process affected the conductance.
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Affiliation(s)
- Kohei Yamada
- Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Tokushi Kizuka
- Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
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11
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Rincón-García L, Ismael AK, Evangeli C, Grace I, Rubio-Bollinger G, Porfyrakis K, Agraït N, Lambert CJ. Molecular design and control of fullerene-based bi-thermoelectric materials. NATURE MATERIALS 2016; 15:289-93. [PMID: 26641017 DOI: 10.1038/nmat4487] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/26/2015] [Indexed: 05/03/2023]
Abstract
Molecular junctions are a versatile test bed for investigating nanoscale thermoelectricity and contribute to the design of new cost-effective environmentally friendly organic thermoelectric materials. It was suggested that transport resonances associated with discrete molecular levels could play a key role in thermoelectric performance, but no direct experimental evidence has been reported. Here we study single-molecule junctions of the endohedral fullerene Sc3N@C80 connected to gold electrodes using a scanning tunnelling microscope. We find that the magnitude and sign of the thermopower depend strongly on the orientation of the molecule and on applied pressure. Our calculations show that Sc3N inside the fullerene cage creates a sharp resonance near the Fermi level, whose energetic location, and hence the thermopower, can be tuned by applying pressure. These results reveal that Sc3N@C80 is a bi-thermoelectric material, exhibiting both positive and negative thermopower, and provide an unambiguous demonstration of the importance of transport resonances in molecular junctions.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
| | - Ali K Ismael
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
- Department of Physics, College of Education for Pure Science, Tikrit University, Tikreet 34001, Iraq
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Iain Grace
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | | | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia, E-28049 Madrid, Spain
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YW, UK
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12
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Rincón-García L, Evangeli C, Rubio-Bollinger G, Agraït N. Thermopower measurements in molecular junctions. Chem Soc Rev 2016; 45:4285-306. [DOI: 10.1039/c6cs00141f] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The measurement of thermopower in molecular junctions offers complementary information to conductance measurements and is becoming essential for the understanding of transport processes at the nanoscale.
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Affiliation(s)
- Laura Rincón-García
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
| | - Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
| | - Gabino Rubio-Bollinger
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Universitario de Ciencia de Materiales “Nicolás Cabrera”
| | - Nicolás Agraït
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
- Universidad Autónoma de Madrid
- E-28049 Madrid
- Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia IMDEA-Nanociencia
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Larson JM, Bharath SC, Cullen WG, Reutt-Robey JE. Scanning MWCNT-Nanopipette and Probe Microscopy: Li Patterning and Transport Studies. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:4946-4958. [PMID: 26182911 DOI: 10.1002/smll.201500999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Indexed: 06/04/2023]
Abstract
A carbon-nanotube-enabling scanning probe technique/nanotechnology for manipulating and measuring lithium at the nano/mesoscale is introduced. Scanning Li-nanopipette and probe microscopy (SLi-NPM) is based on a conductive atomic force microscope (AFM) cantilever with an open-ended multi-walled carbon nanotube (MWCNT) affixed to its apex. SLi-NPM operation is demonstrated with a model system consisting of a Li thin film on a Si(111) substrate. By control of bias, separation distance, and contact time, attograms of Li can be controllably pipetted to or from the MWCNT tip. Patterned surface Li features are then directly probed via noncontact AFM measurements with the MWCNT tip. The subsequent decay of Li features is simulated with a mesoscale continuum model, developed here. The Li surface diffusion coefficient for a four (two) Li layer thick film is measured as D=8(±1.2)×10(-15) cm(2) s(-1) (D=1.75(±0.15)×10(-15) cm(2) s(-1)). Dual-Li pipetting/measuring with SLi-NPM enables a broad range of time-dependent Li and nanoelectrode characterization studies of fundamental importance to energy-storage research.
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Affiliation(s)
- Jonathan M Larson
- Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA
| | - Satyaveda C Bharath
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD, 20742-4454, USA
- US Army Research Laboratory, Aberdeen, MD, 21005, USA
| | - William G Cullen
- Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA
- National Institute of Standards and Technology, Gaithersburg, MD, 20899-1070, USA
| | - Janice E Reutt-Robey
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD, 20742-4454, USA
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14
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Evangeli C, Matt M, Rincón-García L, Pauly F, Nielaba P, Rubio-Bollinger G, Cuevas JC, Agraït N. Quantum thermopower of metallic atomic-size contacts at room temperature. NANO LETTERS 2015; 15:1006-11. [PMID: 25607343 DOI: 10.1021/nl503853v] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report conductance and thermopower measurements of metallic atomic-size contacts, namely gold and platinum, using a scanning tunneling microscope (STM) at room temperature. We find that few-atom gold contacts have an average negative thermopower, whereas platinum contacts present a positive thermopower, showing that for both metals, the sign of the thermopower in the nanoscale differs from that of bulk wires. We also find that the magnitude of the thermopower exhibits minima at the maxima of the conductance histogram in the case of gold nanocontacts while for platinum it presents large fluctuations. Tight-binding calculations and Green's function techniques, together with molecular dynamics simulations, show that these observations can be understood in the context of the Landauer-Büttiker picture of coherent transport in atomic-scale wires. In particular, we show that the differences in the thermopower between these two metals are due to the fact that the elastic transport is dominated by the 6s orbitals in the case of gold and by the 5d orbitals in the case of platinum.
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Affiliation(s)
- Charalambos Evangeli
- Departamento de Física de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , E-28049 Madrid, Spain
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15
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Kawai S, Sadeghi A, Xu F, Peng L, Pawlak R, Glatzel T, Willand A, Orita A, Otera J, Goedecker S, Meyer E. Obtaining detailed structural information about supramolecular systems on surfaces by combining high-resolution force microscopy with ab initio calculations. ACS NANO 2013; 7:9098-9105. [PMID: 23991942 DOI: 10.1021/nn403672m] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
State-of-the art experimental techniques such as scanning tunneling microscopy have great difficulties in extracting detailed structural information about molecules adsorbed on surfaces. By combining atomic force microscopy and Kelvin probe force microscopy with ab initio calculations, we demonstrate that we can obtain a wealth of detailed structural information about the molecule itself and its environment. Studying an FFPB molecule on a gold surface, we are able to determine its exact location on the surface, the nature of its bonding properties with neighboring molecules that lead to the growth of one-dimensional strips, and the internal torsions and bendings of the molecule.
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Affiliation(s)
- Shigeki Kawai
- Department of Physics, University of Basel , Klingbergstrasse 82, 4056 Basel, Switzerland
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16
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Barzilai S, Tavazza F, Levine LE. Ab initio study of the mechanical and transport properties of pure and contaminated silver nanowires. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:325303. [PMID: 23846722 DOI: 10.1088/0953-8984/25/32/325303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The mechanical properties and conductance of contaminated and pure silver nanowires were studied using density functional theory (DFT) calculations. Several nanowires containing O2 on their surfaces were elongated along two different directions. All of the NWs thinned down to single atom chains. In most simulations, the breaking force was not affected by the presence of the O2, and similar fracture strengths of ≈1 nN were computed for the pure and impure NWs. When the O2 became incorporated in the single atom chain, the fracture occurred at the Ag-O bond and a lower fracture strength was found. All of the simulations showed that the impurity interacted with the silver atoms to reduce the electron density in its nearby vicinity. A variety of conductance effects were observed depending on the location of the impurity. When the impurity migrated during the elongation to the thinnest part of the NW, it reduced the conductance significantly, and an ≈1 G0 conductance (usually associated with a single atom chain) was calculated for three- and two-dimensional structures. When the impurity was adjacent to the single atom chain, the conductance reduced almost to zero. However, when it stayed far from the thinnest part of the NW, the impurity had only a small influence on the conductance.
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Affiliation(s)
- S Barzilai
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8553, Gaithersburg, MD 20899, USA.
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17
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Klein H, Leoni T, Zoubkoff R, Dumas P, Saúl A. Conductance fluctuations in gold point contacts: an atomistic picture. NANOTECHNOLOGY 2012; 23:235707. [PMID: 22595959 DOI: 10.1088/0957-4484/23/23/235707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper concerns an experimental and theoretical study of the transition between two consecutive conductance plateaus as obtained in breaking gold contact experiments. The experimental measurements performed at 100 K with a scanning tunneling microscope and variable elongation speeds show that the transitions between consecutive plateaus can appear in the conductance traces as an abrupt conductance step, a smooth quasicontinuous change or as large amplitude conductance fluctuations. The theoretical calculations based on a non-orthogonal tight-binding Hamiltonian have shown that for a given deformation there are several structures having close and competing energies.We discuss the relation between the temperature, sampling frequency, stretching speed and energy barriers which can explain the conditions for the observation of the three kinds of conductance traces.
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Affiliation(s)
- Hubert Klein
- CINaM, Aix-Marseille Université-CNRS, Campus de Luminy, Case 913, Marseille Cedex 9, France
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18
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Pobelov IV, Mészáros G, Yoshida K, Mishchenko A, Gulcur M, Bryce MR, Wandlowski T. An approach to measure electromechanical properties of atomic and molecular junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:164210. [PMID: 22466399 DOI: 10.1088/0953-8984/24/16/164210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We describe a new setup for simultaneous measurements of force and current in conductive nanocontacts in a liquid environment with a high sampling rate and resolution. A lab-built current-to-voltage converter allows measurements of the current over seven orders of magnitude. As examples, we studied conductances and mechanical forces upon formation and breaking of gold atomic contacts and of two molecular junctions containing 1,2-di(4-pyridyl)ethyne (M1) and 1,4-di(4-pyridyl)buta-1,3-diyne (M2). We found that the forces required to deform or break gold atomic contacts depend critically on the surrounding medium. Further, they show non-linear behaviour in dependence of the number N of gold atoms detached. The electromechanical properties of the two types of molecular junctions upon stretching were analysed by correlating breaking forces with simultaneously measured junction conductances. A rather complex behaviour in a wide range of forces was discovered. Comparison of the current-probe atomic force microscopy experiments on the rupture of molecular junctions with STM-based break junction experiments enables the assignment of breaking forces of molecular junctions to the corresponding junction conductances.
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Affiliation(s)
- Ilya V Pobelov
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland.
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19
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Matthews TS, Sawyer C, Ogletree DF, Liliental-Weber Z, Chrzan DC, Wu J. Large reaction rate enhancement in formation of ultrathin AuSi eutectic layers. PHYSICAL REVIEW LETTERS 2012; 108:096102. [PMID: 22463651 DOI: 10.1103/physrevlett.108.096102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Indexed: 05/31/2023]
Abstract
Metal-semiconductor eutectic liquids play a key role in both the fundamental understanding of atomic interactions and nanoscale synthesis and catalysis. At reduced sizes they exhibit properties distinct from the bulk. In this work we show an unusual effect that the formation of AuSi eutectic liquid layers is much easier for smaller thicknesses. The alloying reaction rate is enhanced by over 20 times when the thickness is reduced from 300 to 20 nm. The strong enhancement is attributed to a strain-induced increase in the chemical potential of the solid layer prior to the alloying reaction.
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Affiliation(s)
- Tyler S Matthews
- Department of Materials Science & Engineering, University of California, Berkeley, California 94720, USA
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20
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Iacovella CR, French WR, Cook BG, Kent PRC, Cummings PT. Role of polytetrahedral structures in the elongation and rupture of gold nanowires. ACS NANO 2011; 5:10065-10073. [PMID: 22040227 DOI: 10.1021/nn203941r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report comprehensive high-accuracy molecular dynamics simulations using the ReaxFF force field to explore the structural changes that occur as Au nanowires are elongated, establishing trends as a function of both temperature and nanowire diameter. Our simulations and subsequent quantitative structural analysis reveal that polytetrahedral structures (e.g., icosahedra) form within the "amorphous" neck regions, most prominently for systems with small diameter at high temperature. We demonstrate that the formation of polytetrahedra diminishes the conductance quantization as compared to systems without this structural motif. We demonstrate that use of the ReaxFF force field, fitted to high-accuracy first-principles calculations of Au, combines the accuracy of quantum calculations with the speed of semiempirical methods.
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Affiliation(s)
- Christopher R Iacovella
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235-1604, United States
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21
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Ono T, Tsukamoto S, Egami Y, Fujimoto Y. Real-space calculations for electron transport properties of nanostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:394203. [PMID: 21921313 DOI: 10.1088/0953-8984/23/39/394203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Recent developments in the fabrication and investigation of conductors of atomic dimensions have stimulated a large number of experimental and theoretical studies on these nanoscale devices. In this paper, we introduce examples presenting the efficiencies and advantages of a first-principles transport calculation scheme based on the real-space finite-difference (RSFD) formalism and the overbridging boundary-matching (OBM) method. The RSFD method does not suffer from the artificial periodicity problems that arise in methods using plane-wave basis sets or the linear dependence problems that occur in methods using atomic basis sets. Moreover, the algorithm of the RSFD method is suitable for massively parallel computers and, thus, the combination of the RSFD and OBM methods enables us to execute first-principles transport calculations using large models. To demonstrate the advantages of this method, several applications of the transport calculations in various systems ranging from jellium nanowires to the tip and surface system of scanning tunneling microscopy are presented.
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Affiliation(s)
- Tomoya Ono
- Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
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22
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Tavazza F, Smith DT, Levine LE, Pratt JR, Chaka AM. Electron transport in gold nanowires: stable 1-, 2- and 3-dimensional atomic structures and noninteger conduction states. PHYSICAL REVIEW LETTERS 2011; 107:126802. [PMID: 22026784 DOI: 10.1103/physrevlett.107.126802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 06/13/2011] [Indexed: 05/31/2023]
Abstract
Experimental conductivity measurements made during highly stable tensile deformation of Au nanowires show a rich variety of behaviors, including noninteger quantum conductance plateaus, transitions, and slopes. Using tight binding conductance calculations on simulated nanowires previously deformed using density functional theory, we demonstrate that all of these phenomena arise from structural transitions between deeply metastable ordered atomic configurations that self-organize during tensile deformation.
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Affiliation(s)
- F Tavazza
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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23
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Abstract
We introduce quantum point contact microscopy (QPCM) as a novel method for surface characterization, where the conductance through a quantum point contact formed by a metal atom between the tip of a scanning tunneling microscope and the surface is mapped across the surface. Application of QPCM to copper and gold (111) shows reproducibly atomic resolution, on gold (111) the alternating atomic stacking of the surface reconstruction is observed in real space. The perspectives for chemical sensitivity in QPCM images are demonstrated for an iron-platinum surface alloy where we observe local variations of the transport current due to changes in the chemical environment of the point contact.
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Affiliation(s)
- Yong-Hui Zhang
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
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24
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Lu Y, Peng C, Ganesan Y, Huang JY, Lou J. Quantitative in situ TEM tensile testing of an individual nickel nanowire. NANOTECHNOLOGY 2011; 22:355702. [PMID: 21817781 DOI: 10.1088/0957-4484/22/35/355702] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this paper, we have demonstrated the usage of a novel micro-mechanical device (MMD) to perform quantitative in situ tensile tests on individual metallic nanowires inside a transmission electron microscope (TEM). Our preliminary experiment on a 360 nm diameter nickel nanowire showed that the sample fractured at an engineering stress of ∼ 1.2 GPa and an engineering strain of ∼ 4%, which is consistent with earlier experiments performed inside a scanning electron microscope (SEM). With in situ high resolution TEM imaging and diffraction capabilities, this novel experimental set-up could provide unique opportunities to reveal the underlying deformation and damage mechanisms for metals at the nanoscale.
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Affiliation(s)
- Yang Lu
- Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005, USA
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25
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Arroyo CR, Leary E, Castellanos-Gómez A, Rubio-Bollinger G, González MT, Agraït N. Influence of Binding Groups on Molecular Junction Formation. J Am Chem Soc 2011; 133:14313-9. [DOI: 10.1021/ja201861k] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
| | - Edmund Leary
- Instituto Madrileño de Estudios Advanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | | | | | - M. Teresa González
- Instituto Madrileño de Estudios Advanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
| | - Nicolás Agraït
- Instituto Madrileño de Estudios Advanzados en Nanociencia (IMDEA-Nanociencia), Ciudad Universitaria de Cantoblanco, E-28049 Madrid, Spain
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26
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Discrete plasticity in sub-10-nm-sized gold crystals. Nat Commun 2011; 1:144. [PMID: 21266994 PMCID: PMC3105591 DOI: 10.1038/ncomms1149] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 11/25/2010] [Indexed: 11/17/2022] Open
Abstract
Although deformation processes in submicron-sized metallic crystals are well documented, the direct observation of deformation mechanisms in crystals with dimensions below the sub-10-nm range is currently lacking. Here, through in situ high-resolution transmission electron microscopy (HRTEM) observations, we show that (1) in sharp contrast to what happens in bulk materials, in which plasticity is mediated by dislocation emission from Frank-Read sources and multiplication, partial dislocations emitted from free surfaces dominate the deformation of gold (Au) nanocrystals; (2) the crystallographic orientation (Schmid factor) is not the only factor in determining the deformation mechanism of nanometre-sized Au; and (3) the Au nanocrystal exhibits a phase transformation from a face-centered cubic to a body-centered tetragonal structure after failure. These findings provide direct experimental evidence for the vast amount of theoretical modelling on the deformation mechanisms of nanomaterials that have appeared in recent years. Deformations in nanocrystals smaller than 10 nm are not well understood. The authors perform compression high-resolution transmission electron microscopy studies of gold nanoparticles, and determine that the nanoparticles deform through the emission of partial dislocations from free surfaces.
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27
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Wang F, Gao Y, Zhu T, Zhao J. Shock-induced breaking of the nanowire with the dependence of crystallographic orientation and strain rate. NANOSCALE RESEARCH LETTERS 2011; 6:291. [PMID: 21711854 PMCID: PMC3211357 DOI: 10.1186/1556-276x-6-291] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 04/05/2011] [Indexed: 05/18/2023]
Abstract
The failure of the metallic nanowire has raised concerns due to its applied reliability in nanoelectromechanical system. In this article, the breaking failure is studied for the [100], [110], and [111] single-crystal copper nanowires at different strain rates. The statistical breaking position distributions of the nanowires have been investigated to give the effects of strain rate and crystallographic orientation on micro-atomic fluctuation in the symmetric stretching of the nanowires. When the strain rate is less than 0.26% ps-1, macro-breaking position distributions exhibit the anisotropy of micro-atomic fluctuation. However, when the strain rate is larger than 3.54% ps-1, the anisotropy is not obvious because of strong symmetric shocks.
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Affiliation(s)
- Fenying Wang
- Key Laboratory of Analytical Chemistry for Life Sciences, Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008, P. R. China
| | - Yajun Gao
- Key Laboratory of Analytical Chemistry for Life Sciences, Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008, P. R. China
| | - Tiemin Zhu
- Key Laboratory of Analytical Chemistry for Life Sciences, Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008, P. R. China
| | - Jianwei Zhao
- Key Laboratory of Analytical Chemistry for Life Sciences, Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210008, P. R. China
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28
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Wang F, Gao Y, Zhu T, Zhao J. Shock-induced breaking in the gold nanowire with the influence of defects and strain rates. NANOSCALE 2011; 3:1624-1631. [PMID: 21350764 DOI: 10.1039/c0nr00797h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Defects in metallic nanowires have raised concerns about the applied reliability of the nanowires in nanoelectromechanical systems. In this paper, molecular dynamics simulations are used to study the deformation and breaking failure of the [100] single-crystal gold nanowires containing defects at different strain rates. The statistical breaking position distributions of the nanowires show mechanical shocks play a critical role in the deformation of nanowires at different strain rates, and deformation mechanism of the nanowire containing defects is based on a competition between shocks and defects in the deformation process of the nanowire. At low strain rate of 1.0% ps(-1), defect ratio of 2% has changed the deformation mechanism because micro-atomic fluctuation is in an equilibrium state. However, owing to strong symmetric shocks, the sensitivity of defects is not obvious before a defect ratio of 25% at high strain rate of 5.0% ps(-1).
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Affiliation(s)
- Fenying Wang
- Key Laboratory of Analytical Chemistry for Life Sciences, Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210008, PR China
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29
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Wlasenko A, Soltani F, Zakopcan D, Sinton D, Steeves GM. Diffusion-limited and advection-driven electrodeposition in a microfluidic channel. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:021601. [PMID: 20365568 DOI: 10.1103/physreve.81.021601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Indexed: 05/29/2023]
Abstract
Self-terminating electrochemical fabrication was used within a microfluidic channel to create a junction between two Au electrodes separated by a gap of 75 microm . During the electrochemical process of etching from the anode to deposition at the cathode, flow could be applied in the anode-to-cathode direction. Without applied flow, dendritic growth and dense branching morphologies were typically observed at the cathode. The addition of applied flow resulted in a densely packed gold structure that filled the channel. A computer simulation was developed to explore regimes where the diffusion, flow, and electric field between the electrodes individually dominated growth. The model provided good qualitative agreement relating flow to the experimental results. The model was also used to contrast the effects of open and closed boundaries and electric field strength, as factors related to tapering.
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Affiliation(s)
- A Wlasenko
- Department of Physics and Astronomy, University of Victoria, PO Box 3055, STN CSC, Victoria, British Columbia, Canada V8W 3P6
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30
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Mei J, Li J, Ni Y, Wang H. Multiscale simulation of indentation, retraction and fracture processes of nanocontact. NANOSCALE RESEARCH LETTERS 2010; 5:692-700. [PMID: 20672044 PMCID: PMC2894359 DOI: 10.1007/s11671-010-9533-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 01/05/2010] [Indexed: 05/27/2023]
Abstract
The process of nanocontact including indentation and retraction between a large Ni tip and a Cu substrate is investigated using quasicontinuum (QC) method. The multiscale model reveals that significant plastic deformation occurs during the process of nanocontact between Ni tip and Cu substrate. Plastic deformation is observed in an area as large as 20 nm wide and 10 nm thick beneath Ni tip during the indentation and retraction. Also, plastic deformation at a deep position in the Cu substrate does not disappear after the neck failure. The analysis of generalized planar fault energy curve shows that there is a strong tendency for deformation twinning in Cu substrate. However, deformation twinning will be retarded during indentation due to the high stress intensity caused by stepped surface of Ni tip. The abrupt drop of load curve during tip retraction is attributed to the two different fracture mechanisms. One is atomic rearrangement near the interface of Ni tip and Cu substrate at the initial stage of neck fracture, the other is shear behavior of adjacent {111} planes at the necking point. A comparison of the critical load and critical contact radius for neck fracture is also made between theoretical values and our numerical results.
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Affiliation(s)
- Jifa Mei
- Department of Mechanics and Engineering Science, Fudan University, 200433, Shanghai, China.
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31
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Todorov TN, Hoekstra J, Sutton AP. Current-induced forces in atomic-scale conductors. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/13642810008208601] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- T. N. Todorov
- a Department of Materials , University of Oxford , Parks Road, Oxford OX1 3PH, UK
- b School of Mathematics and Physics, The Queen's University of Belfast , Belfast BT7 INN, UK E-mail:
| | - J. Hoekstra
- a Department of Materials , University of Oxford , Parks Road, Oxford OX1 3PH, UK
| | - A. P. Sutton
- a Department of Materials , University of Oxford , Parks Road, Oxford OX1 3PH, UK
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32
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Liu Y, Wang F, Zhao J, Jiang L, Kiguchi M, Murakoshi K. Theoretical investigation on the influence of temperature and crystallographic orientation on the breaking behavior of copper nanowire. Phys Chem Chem Phys 2009; 11:6514-9. [PMID: 19809684 DOI: 10.1039/b902795e] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, molecular dynamics simulations have been conducted to study the mechanical stretching of copper nanowires which will finally lead to the formation of suspended liner atomic chains. A total of 2700 samples have been investigated to achieve a comprehensive understanding of the influence of temperature and orientation on the formation of linear atomic chains. Our results prove that linear atomic chains do exist for [100], [111] and [110] crystallographic directions. Stretching along the [111] direction exhibits a higher probability in forming the two-atom contact than that along the [110] and [100] directions. However, for longer linear atomic chains, there emerges a reversed trend. In addition, increasing temperature may decrease the formation probability for stretching along [111] and [110] directions, but this influence is less obvious for that along the [100] direction.
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Affiliation(s)
- Yunhong Liu
- Key Laboratory of Analytical Chemistry for Life Science (Ministry of Education), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China 210008
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33
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Kim T, Myung S, Kim TH, Hong S. Robust single-nanoparticle probe for contact-mode analysis and dip-pen nanolithography. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:1072-1075. [PMID: 18651711 DOI: 10.1002/smll.200701102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Taekyeong Kim
- School of Physics, Seoul National University NS50 Shilim-Dong, Kwanak-Gu, Seoul 151-742, Korea
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34
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Quantitative characterization of crosstalk effects for friction force microscopy with scan-by-probe SPMs. Ultramicroscopy 2008; 108:642-5. [DOI: 10.1016/j.ultramic.2007.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 09/24/2007] [Accepted: 10/10/2007] [Indexed: 11/24/2022]
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35
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Qi Y, Guan D, Jiang Y, Zheng Y, Liu C. How do oxygen molecules move into silver contacts and change their electronic transport properties? PHYSICAL REVIEW LETTERS 2006; 97:256101. [PMID: 17280369 DOI: 10.1103/physrevlett.97.256101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2006] [Indexed: 05/13/2023]
Abstract
We present first principles simulations of the elongation process of the silver contact at the O2 atmosphere. The electronic transport properties are calculated. It is found that the O2 molecule can move into the silver contact during elongation and the corresponding mechanism is given. We demonstrate that there are two transmission channels around the Fermi level in an Ag-O2 contact system. The breaking process of an Ag-Ag bond is found to play an important role in determining the evolution of the system conductance during the elongation.
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Affiliation(s)
- Yuanhua Qi
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, China
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36
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Sasaki T, Ono T, Hirose K. Order-N first-principles calculation method for self-consistent ground-state electronic structures of semi-infinite systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:056704. [PMID: 17280018 DOI: 10.1103/physreve.74.056704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Indexed: 05/13/2023]
Abstract
We present an efficient and highly accurate first-principles calculation method with linear system-size scaling to determine the self-consistent ground-state electron-charge densities of nanostructures suspended between semi-infinite bulks by directly minimizing the energy functional. By making efficient use of the advantages of the real-space finite-difference method, we can impose arbitrary boundary conditions on models and employ spatially localized orbitals. These advantages enable us to calculate the ground-state electron-charge densities in semi-infinite systems. Examples of electronic structure calculations for a one-dimensional case and a conductance calculation for sodium nanowires are presented. The calculated electronic structure of the one-dimensional system agrees well with the exact analytical solution, and the conduction properties of the sodium nanowires are consistent with experimental and other theoretical results. These results imply that our procedure enables us to accurately compute self-consistent electronic structures of semi-infinite systems.
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Affiliation(s)
- Takashi Sasaki
- Department of Precision Science and Technology, Osaka University, Suita, Osaka 565-0871, Japan
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37
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Beyer MK, Clausen-Schaumann H. Mechanochemistry: The Mechanical Activation of Covalent Bonds. Chem Rev 2005; 105:2921-48. [PMID: 16092823 DOI: 10.1021/cr030697h] [Citation(s) in RCA: 717] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martin K Beyer
- Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
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Wu B, Heidelberg A, Boland JJ. Mechanical properties of ultrahigh-strength gold nanowires. NATURE MATERIALS 2005; 4:525-9. [PMID: 15937490 DOI: 10.1038/nmat1403] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Accepted: 04/18/2005] [Indexed: 05/02/2023]
Abstract
Nanowires have attracted considerable interest as nanoscale interconnects and as the active components of both electronic and electromechanical devices. Nanomechanical measurements are a challenge, but remain key to the development and processing of novel nanowire-based devices. Here, we report a general method to measure the spectrum of nanowire mechanical properties based on nanowire bending under the lateral load from an atomic force microscope tip. We find that for Au nanowires, Young's modulus is essentially independent of diameter, whereas the yield strength is largest for the smallest diameter wires, with strengths up to 100 times that of bulk materials, and substantially larger than that reported for bulk nanocrystalline metals (BNMs). In contrast to BNMs, nanowire plasticity is characterized by strain-hardening, demonstrating that dislocation motion and pile-up is still operative down to diameters of 40 nm. Possible origins for the different mechanical properties of nanowires and BNMs are discussed.
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Affiliation(s)
- Bin Wu
- Centre for Research on Adaptive Nanostructures and Nanodevices and the Department of Chemistry, Trinity College Dublin, Dublin 2, Ireland
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Tongay S, Dag S, Durgun E, Senger RT, Ciraci S. Atomic and electronic structure of carbon strings. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2005; 17:3823-3836. [PMID: 21690699 DOI: 10.1088/0953-8984/17/25/009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper presents an extensive study of various string and tubular structures formed by carbon atomic chains. Our study is based on first-principles pseudopotential plane wave and finite-temperature ab initio molecular dynamics calculations. Infinite- and finite-length carbon chains exhibit unusual mechanical and electronic properties such as large cohesive energy, axial strength, high conductance, and overall structural stability even at high temperatures. They are suitable for structural and chemical functionalizations. Owing to their flexibility and reactivity they can form linear chain, ring, helix, two-dimensional rectangular and honeycomb grids, three-dimensional cubic networks, and tubular structures. Metal-semiconductor heterostructures and various quantum structures, such as multiple quantum wells and double-barrier resonant tunnelling structures, can be formed from the junctions of metallic carbon and semiconducting BN linear chains. Analysis of atomic and electronic structures of these periodic, finite, and doped structures reveals fundamentally and technologically interesting features, such as structural instabilities and chiral currents. The double covalent bonding of carbon atoms depicted through self-consistent charge density analysis underlies the chemical, mechanical, and electronic properties.
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Affiliation(s)
- S Tongay
- Department of Physics, Bilkent University, 06800 Ankara, Turkey
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Senger RT, Dag S, Ciraci S. Chiral single-wall gold nanotubes. PHYSICAL REVIEW LETTERS 2004; 93:196807. [PMID: 15600867 DOI: 10.1103/physrevlett.93.196807] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2004] [Indexed: 05/24/2023]
Abstract
Based on first-principles calculations we show that gold atoms can form both freestanding and tip-suspended chiral single-wall nanotubes composed of helical atomic strands. The freestanding, infinite (5,5) tube is found to be energetically the most favorable. While energetically less favorable, the experimentally observed (5,3) tube stretching between two tips corresponds to a local minimum in the string tension. Similarly, the (4,3) tube is predicted as a favorable structure yet to be observed experimentally. Analysis of band structure, charge density, and quantum ballistic conductance suggests that the current on these wires is less chiral than expected, and there is no direct correlation between the numbers of conduction channels and helical strands.
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Affiliation(s)
- R T Senger
- Department of Physics, Bilkent University, 06800 Ankara, Turkey
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Rubio-Bollinger G, Joyez P, Agraït N. Metallic adhesion in atomic-size junctions. PHYSICAL REVIEW LETTERS 2004; 93:116803. [PMID: 15447366 DOI: 10.1103/physrevlett.93.116803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Indexed: 05/24/2023]
Abstract
We report high resolution simultaneous measurements of electrical conductance and force gradient between two sharp gold tips as their separation is varied from the tunneling distance to atomic-size contact. The use of atomically sharp tips minimizes van der Waals interaction, making it possible to identify the short-range metallic adhesion contribution to the total force.
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Affiliation(s)
- G Rubio-Bollinger
- Laboratorio de Bajas Temperaturas, Department Física de la Materia Condensada C-III, Instituto Universitario de Ciencia de Materiales Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
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Hui L, Pederiva F, Wang GH, Wang BL. Local clusters and defects in one-dimensional gold wires. J Chem Phys 2003. [DOI: 10.1063/1.1615960] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Smit RHM, Untiedt C, Rubio-Bollinger G, Segers RC, van Ruitenbeek JM. Observation of a parity oscillation in the conductance of atomic wires. PHYSICAL REVIEW LETTERS 2003; 91:076805. [PMID: 12935043 DOI: 10.1103/physrevlett.91.076805] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2003] [Indexed: 05/24/2023]
Abstract
Using a scanning tunnel microscope or mechanically controllable break junctions atomic contacts for Au, Pt, and Ir are pulled to form chains of atoms. We have recorded traces of conductance during the pulling process and averaged these for a large number of contacts. An oscillatory evolution of conductance is observed during the formation of the monoatomic chain suggesting a dependence on the numbers of atoms forming the chain being even or odd. This behavior is not only observed for the monovalent metal Au, as was predicted, but is also found for the other chain-forming metals, suggesting it to be a universal feature of atomic wires.
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Affiliation(s)
- R H M Smit
- Kamerlingh Onnes Laboratorium, Leiden University, P.O. Box 9504, NL-2300 RA Leiden, The Netherlands
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Kang JW, Hwang HJ. An atomistic simulation study of cylindrical ultrathin Cu nanowires. MOLECULAR SIMULATION 2002. [DOI: 10.1080/0892702021000011052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Rodrigo JG, García-Martín A, Sáenz JJ, Vieira S. Quantum conductance in semimetallic bismuth nanocontacts. PHYSICAL REVIEW LETTERS 2002; 88:246801. [PMID: 12059321 DOI: 10.1103/physrevlett.88.246801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2001] [Indexed: 05/23/2023]
Abstract
Electronic transport properties of bismuth nanocontacts are analyzed using a low temperature scanning tunneling microscope. The subquantum steps observed in the conductance versus elongation curves give evidence of atomic rearrangements in the contact. The quantum nature of the conductance reveals itself through peaks in the conductance histograms. The shape of the curves at 77 K is described by a simple gliding mechanism for the contact evolution during elongation. The different behavior at 4 K suggests a transition from light to heavy charge carriers as the contact cross section is decreased.
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Affiliation(s)
- J G Rodrigo
- Instituto Universitario de Ciencia de Materiales Nicolás Cabrera and Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Marszalek PE, Greenleaf WJ, Li H, Oberhauser AF, Fernandez JM. Atomic force microscopy captures quantized plastic deformation in gold nanowires. Proc Natl Acad Sci U S A 2000; 97:6282-6. [PMID: 10841533 PMCID: PMC18594 DOI: 10.1073/pnas.97.12.6282] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Scanning probe microscopy has become a powerful tool to detect structural changes in small clusters of atoms. Herein, we use an atomic force microscope to measure the length of gold nanowire structures during extension and compression cycles. We have found that nanowires elongate under force in quantized steps of up to three integer multiples of 1.76 A and that they shorten spontaneously in steps of 1.52 A. Our results can be explained by the sliding of crystal planes within the gold nanowires creating stacking faults that change the local structure from face-centered cubic to hexagonal close packed. Our data also show that there can be up to three simultaneous slip events, in good agreement with the tetrahedral arrangement of slip planes in a gold crystal. These experiments provide direct evidence for the mechanism underlying the plastic deformation of a nanowire. A similar approach can be used to examine the atomic events underlying the plastic failure of other metals and their alloys.
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Affiliation(s)
- P E Marszalek
- Department of Physiology and Biophysics, Mayo Foundation, Rochester, MN 55905, USA
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Electrical testing of gold nanostructures by conducting atomic force microscopy. ACTA ACUST UNITED AC 2000. [DOI: 10.1116/1.591353] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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