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Qiao Z, Ying Z, Zhou X, Feng K, Shi L. Hydrogen Bond Network Shaping Proton Penetration Behavior across Two-Dimensional Nanoporous Materials. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39315847 DOI: 10.1021/acsami.4c11275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
In this study, we investigate aqueous proton penetration behavior across four types of two-dimensional (2D) nanoporous materials with similar pore sizes using extensive ReaxFF molecular dynamics simulations. The results reveal significant differences in proton penetration energy barriers among the four kinds of 2D materials, despite their comparable pore sizes. Our analysis indicates that these variations in energy barriers stem from differences in the hydrogen bond (HB) network formed between the 2D nanoporous materials and the aqueous environment. The HB network can be classified into two categories: those formed between the surface of the 2D nanoporous materials and the aqueous environment, and those formed between the edge atoms of the nanopores and the water molecules inside the pores. A strong HB network formed between the surface of the 2D nanoporous materials and the aqueous environment induces an orientational preference of water molecules, resulting in an aggregated water layer with high density. This high-density water region traps protons, making it difficult for them to escape and penetrate the nanopores. On the other hand, a strong HB network formed between the edge atoms of the nanopores and the water molecules inside the pores impedes the rotation and migration of water molecules, further inhibiting proton penetration behavior. To facilitate the proton penetration process, in addition to a sufficiently large pore size, a weak HB network between the 2D nanoporous material and the aqueous environment is necessary.
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Affiliation(s)
- Zilin Qiao
- Center of Nanomaterials for Renewable Energy (CNRE), State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Zhixuan Ying
- Center of Nanomaterials for Renewable Energy (CNRE), State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Xi Zhou
- Center of Nanomaterials for Renewable Energy (CNRE), State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Kejie Feng
- Center of Nanomaterials for Renewable Energy (CNRE), State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Le Shi
- Center of Nanomaterials for Renewable Energy (CNRE), State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China
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Rogal J, Díaz Leines G. Controlling crystallization: what liquid structure and dynamics reveal about crystal nucleation mechanisms. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220249. [PMID: 37211029 DOI: 10.1098/rsta.2022.0249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/06/2022] [Indexed: 05/23/2023]
Abstract
Over recent years, molecular simulations have provided invaluable insights into the microscopic processes governing the initial stages of crystal nucleation and growth. A key aspect that has been observed in many different systems is the formation of precursors in the supercooled liquid that precedes the emergence of crystalline nuclei. The structural and dynamical properties of these precursors determine to a large extent the nucleation probability as well as the formation of specific polymorphs. This novel microscopic view on nucleation mechanisms has further implications for our understanding of the nucleating ability and polymorph selectivity of nucleating agents, as these appear to be strongly linked to their ability in modifying structural and dynamical characteristics of the supercooled liquid, namely liquid heterogeneity. In this perspective, we highlight recent progress in exploring the connection between liquid heterogeneity and crystallization, including the effects of templates, and the potential impact for controlling crystallization processes. This article is part of a discussion meeting issue 'Supercomputing simulations of advanced materials'.
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Affiliation(s)
- Jutta Rogal
- Department of Chemistry, New York University, New York, NY 10003, USA
- Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Grisell Díaz Leines
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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Lee SY, Kim M, Won TK, Back SH, Hong Y, Kim BS, Ahn DJ. Janus regulation of ice growth by hyperbranched polyglycerols generating dynamic hydrogen bonding. Nat Commun 2022; 13:6532. [PMID: 36319649 PMCID: PMC9626502 DOI: 10.1038/s41467-022-34300-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022] Open
Abstract
In this study, a new phenomenon describing the Janus effect on ice growth by hyperbranched polyglycerols, which can align the surrounding water molecules, has been identified. Even with an identical polyglycerol, we not only induced to inhibit ice growth and recrystallization, but also to promote the growth rate of ice that is more than twice that of pure water. By investigating the polymer architecture and population, we found that the stark difference in the generation of quasi-structured H2O molecules at the ice/water interface played a crucial role in the outcome of these opposite effects. Inhibition activity was induced when polymers at nearly fixed loci formed steady hydrogen bonding with the ice surface. However, the formation-and-dissociation dynamics of the interfacial hydrogen bonds, originating from and maintained by migrating polymers, resulted in an enhanced quasi-liquid layer that facilitated ice growth. Such ice growth activity is a unique property unseen in natural antifreeze proteins or their mimetic materials.
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Affiliation(s)
- Sang Yup Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea
- The w:i Interface Augmentation Center, Korea University, Seoul, Republic of Korea
| | - Minseong Kim
- Department of Chemistry, Yonsei University, Seoul, Republic of Korea
| | - Tae Kyung Won
- The w:i Interface Augmentation Center, Korea University, Seoul, Republic of Korea
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Seung Hyuk Back
- The w:i Interface Augmentation Center, Korea University, Seoul, Republic of Korea
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea
| | - Youngjoo Hong
- Department of Chemistry, Yonsei University, Seoul, Republic of Korea
| | - Byeong-Su Kim
- Department of Chemistry, Yonsei University, Seoul, Republic of Korea.
| | - Dong June Ahn
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.
- The w:i Interface Augmentation Center, Korea University, Seoul, Republic of Korea.
- Department of Chemical and Biological Engineering, Korea University, Seoul, Republic of Korea.
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Dragoni D, Behler J, Bernasconi M. Mechanism of amorphous phase stabilization in ultrathin films of monoatomic phase change material. NANOSCALE 2021; 13:16146-16155. [PMID: 34542138 DOI: 10.1039/d1nr03432d] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Elemental antimony has been recently proposed as a promising material for phase change memories with improved performances with respect to the most used ternary chalcogenide alloys. The compositional simplification prevents reliability problems due to demixing of the alloy during memory operation. This is made possible by the dramatic stabilization of the amorphous phase once Sb is confined in an ultrathin film 3-5 nm thick. In this work, we shed light on the microscopic origin of this effect by means of large scale molecular dynamics simulations based on an interatomic potential generated with a machine learning technique. The simulations suggest that the dramatic reduction of the crystal growth velocity in the film with respect to the bulk is due to the effect of nanoconfinement on the fast β relaxation dynamics while the slow α relaxation is essentially unaffected.
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Affiliation(s)
- Daniele Dragoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy.
| | - Jörg Behler
- Institut für Physikalische Chemie, Theoretische Chemie, Universität Göttingen, Tammannstr. 6, 37077 Göttingen, Germany
| | - Marco Bernasconi
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy.
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Dubey V, Dueby S, Daschakraborty S. Breakdown of the Stokes-Einstein relation in supercooled water: the jump-diffusion perspective. Phys Chem Chem Phys 2021; 23:19964-19986. [PMID: 34515269 DOI: 10.1039/d1cp02202d] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Although water is the most ubiquitous liquid it shows many thermodynamic and dynamic anomalies. Some of the anomalies further intensify in the supercooled regime. While many experimental and theoretical studies have focused on the thermodynamic anomalies of supercooled water, fewer studies explored the dynamical anomalies very extensively. This is due to the intricacy of the experimental measurement of the dynamical properties of supercooled water. Violation of the Stokes-Einstein relation (SER), an important relation connecting the diffusion of particles with the viscosity of the medium, is one of the major dynamical anomalies. In absence of experimentally measured viscosity, researchers used to check the validity of SER indirectly using average translational relaxation time or α-relaxation time. Very recently, the viscosity of supercooled water was accurately measured at a wide range of temperatures and pressures. This allowed direct verification of the SER at different temperature-pressure thermodynamic state points. An increasing breakdown of the SER was observed with decreasing temperature. Increasing pressure reduces the extent of breakdown. Although some well-known theories explained the above breakdown, a detailed molecular mechanism was still elusive. Recently, a translational jump-diffusion (TJD) approach has been able to quantitatively explain the breakdown of the SER in pure supercooled water and an aqueous solution of methanol. The objective of this article is to present a detailed and state-of-the-art analysis of the past and present works on the breakdown of SER in supercooled water with a specific focus on the new TJD approach for explaining the breakdown of the SER.
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Affiliation(s)
- Vikas Dubey
- Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
| | - Shivam Dueby
- Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
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Bokova M, Tverjanovich A, Benmore CJ, Fontanari D, Sokolov A, Khomenko M, Kassem M, Ozheredov I, Bychkov E. Unraveling the Atomic Structure of Bulk Binary Ga-Te Glasses with Surprising Nanotectonic Features for Phase-Change Memory Applications. ACS APPLIED MATERIALS & INTERFACES 2021; 13:37363-37379. [PMID: 34318661 DOI: 10.1021/acsami.1c09070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Binary Ge-Te and ternary Ge-Sb-Te systems belong to flagship phase-change materials (PCMs) and are used in nonvolatile memory applications and neuromorphic computing. The working temperatures of these PCMs are limited by low-T glass transition and crystallization phenomena. Promising high-T PCMs may include gallium tellurides; however, the atomic structure and transformation processes for amorphous Ga-Te binaries are simply missing. Using high-energy X-ray diffraction and Raman spectroscopy supported by first-principles simulations, we elucidate the short- and intermediate-range order in bulk glassy GaxTe1-x, 0.17 ≤ x ≤ 0.25, following their thermal, electric, and optical properties, revealing a semiconductor-metal transition above melting. We also show that a phase change in binary Ga-Te is characterized by a very unusual nanotectonic compression with the high internal transition pressure reaching 4-8 GPa, which appears to be beneficial for PCM applications increasing optical and electrical contrast between the SET and RESET states and decreasing power consumption.
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Affiliation(s)
- Maria Bokova
- Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - Andrey Tverjanovich
- Institute of Chemistry, St. Petersburg State University, 198504 St. Petersburg, Russia
| | - Chris J Benmore
- X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Daniele Fontanari
- Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - Anton Sokolov
- Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
- ILIT RAS-Branch of the FSRC "Crystallography and Photonics" RAS, 140700 Shatura, Moscow Region, Russia
| | - Maxim Khomenko
- ILIT RAS-Branch of the FSRC "Crystallography and Photonics" RAS, 140700 Shatura, Moscow Region, Russia
| | - Mohammad Kassem
- Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
| | - Ilya Ozheredov
- ILIT RAS-Branch of the FSRC "Crystallography and Photonics" RAS, 140700 Shatura, Moscow Region, Russia
| | - Eugene Bychkov
- Laboratoire de Physico-Chimie de l'Atmosphère, Université du Littoral Côte d'Opale, 59140 Dunkerque, France
- ILIT RAS-Branch of the FSRC "Crystallography and Photonics" RAS, 140700 Shatura, Moscow Region, Russia
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Zhang H, Wang X, Yu HB, Douglas JF. Dynamic heterogeneity, cooperative motion, and Johari-Goldstein [Formula: see text]-relaxation in a metallic glass-forming material exhibiting a fragile-to-strong transition. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:56. [PMID: 33871722 DOI: 10.1140/epje/s10189-021-00060-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
We investigate the Johari-Goldstein (JG) [Formula: see text]-relaxation process in a model metallic glass-forming (GF) material ([Formula: see text]), previously studied extensively by both frequency-dependent mechanical measurements and simulation studies devoted to equilibrium properties, by molecular dynamics simulations based on validated and optimized interatomic potentials with the primary aim of better understanding the nature of this universal relaxation process from a dynamic heterogeneity (DH) perspective. The present relatively low temperature and long-time simulations reveal a direct correspondence between the JG [Formula: see text]-relaxation time [Formula: see text] and the lifetime of the mobile particle clusters [Formula: see text], defined as in previous DH studies, a relationship dual to the corresponding previously observed relationship between the [Formula: see text]-relaxation time [Formula: see text] and the lifetime of immobile particle clusters [Formula: see text]. Moreover, we find that the average diffusion coefficient D nearly coincides with [Formula: see text] of the smaller atomic species (Al) and that the 'hopping time' associated with D coincides with [Formula: see text] to within numerical uncertainty, both trends being in accord with experimental studies. This indicates that the JG [Formula: see text]-relaxation is dominated by the smaller atomic species and the observation of a direct relation between this relaxation process and rate of molecular diffusion in GF materials at low temperatures where the JG [Formula: see text]-relaxation becomes the prevalent mode of structural relaxation. As an unanticipated aspect of our study, we find that [Formula: see text] exhibits fragile-to-strong (FS) glass formation, as found in many other metallic GF liquids, but this fact does not greatly alter the geometrical nature of DH in this material and the relation of DH to dynamical properties. On the other hand, the temperature dependence of the DH and dynamical properties, such as the structural relaxation time, can be significantly altered from 'ordinary' GF liquids.
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Affiliation(s)
- Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
| | - Xinyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Jack F Douglas
- Material Measurement Laboratory, Materials Science and Engineering Division, National Institute of Standards and Technology(NIST), Gaithersburg, MD, 20899, USA.
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8
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Díaz Leines G, Michaelides A, Rogal J. Interplay of structural and dynamical heterogeneity in the nucleation mechanism in Ni. Faraday Discuss 2021; 235:406-415. [DOI: 10.1039/d1fd00099c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gaining fundamental understanding of crystal nucleation processes in metal alloys is crucial for the development and design of high-performance materials with targeted properties. Yet, crystallizationis a complex non-equilibrium process and,...
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9
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Hoffmann MM, Too MD, Vogel M, Gutmann T, Buntkowsky G. Breakdown of the Stokes-Einstein Equation for Solutions of Water in Oil Reverse Micelles. J Phys Chem B 2020; 124:9115-9125. [PMID: 32924487 DOI: 10.1021/acs.jpcb.0c06124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An experimental study is presented for the reverse micellar system of 15% by mass polydisperse hexaethylene glycol monodecylether (C10E6) in cyclohexane with varying amounts of added water up to 4% by mass. Measurements of viscosity and self-diffusion coefficients were taken as a function of temperature between 10 and 45 °C at varying sample water loads but fixed C10E6/cyclohexane composition. The results were used to inspect the validity of the Stokes-Einstein equation for this system. Unreasonably small reverse average micelle radii and aggregation numbers were obtained with the Stokes-Einstein equation, but reasonable values for these quantities were obtained using the ratio of surfactant-to-cyclohexane self-diffusion coefficients. While bulk viscosity increased with increasing water load, a concurrent expected decrease of self-diffusion coefficient was only observed for the surfactant and water but not for cyclohexane, which showed independence of water load. Moreover, a spread of self-diffusion coefficients was observed for the protons associated with the ethylene oxide repeat unit in samples with polydisperse C10E6 but not in a sample with monodisperse C10E6. These findings were interpreted by the presence of reverse micelle to reverse micelle hopping motions that with higher water load become increasingly selective toward C10E6 molecules with short ethylene oxide repeat units, while those with long ethylene oxide repeat units remain trapped within the reverse micelle because of the increased hydrogen bonding interactions with the water inside the growing core of the reverse micelle. Despite the observed breakdown of the Stokes-Einstein equation, the temperature dependence of the viscosities and self-diffusion coefficients was found to follow Arrhenius behavior over the investigated range of temperatures.
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Affiliation(s)
- Markus M Hoffmann
- Department of Chemistry and Biochemistry, State University of New York College at Brockport, Brockport, New York 14420, United States
| | - Matthew D Too
- Department of Chemistry and Biochemistry, State University of New York College at Brockport, Brockport, New York 14420, United States
| | - Michael Vogel
- Institute of Condensed Matter Physics, Technical University Darmstadt, Hochschulstraße 6, Darmstadt 64289, Germany
| | - Torsten Gutmann
- Institute of Physical Chemistry, Technical University Darmstadt, Alarich-Weiss-Straße 8, Darmstadt D-64287, Germany
| | - Gerd Buntkowsky
- Institute of Physical Chemistry, Technical University Darmstadt, Alarich-Weiss-Straße 8, Darmstadt D-64287, Germany
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Souda R, Aizawa T, Sugiyama N, Takeguchi M. Nucleation and growth of water ice on oxide surfaces: the influence of a precursor to water dissociation. Phys Chem Chem Phys 2020; 22:20515-20523. [PMID: 32966413 DOI: 10.1039/d0cp01897j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have investigated how nucleation and growth processes of ice are influenced by interfacial molecular interactions on some oxide surfaces, such as rutile TiO2(110), TiO2(100), MgO(100), and Al2O3(0001), based on the diffraction patterns of electrons transmitted through ice crystallites under the experimental configuration of reflection high energy electron diffraction (RHEED). The cubic ice Ic grows on the TiO2(110) surface with the epitaxial relationship of (110)Ic//(110)TiO2 and [001]Ic//[11[combining macron]0]TiO2. The epitaxial ice growth tends to be disturbed on the TiO2(110) surface under the presence of oxygen vacancies and adatoms. The result is not simply ascribable to small misfit values between TiO2 and ice Ic lattices (∼2%) because ice grains are formed randomly on TiO2(100). No template effects are identified during ice nucleation on the pristine MgO(100) and Al2O3(0001) surfaces either. The water molecules are chemisorbed weakly on these surfaces as a precursor to dissociation via the acid-base interaction. Such anchored water species act as an inhibitor of epitaxial ice growth because the orientation flexibility of physisorbed water during nucleation is hampered at the interface by the preferential formation of hydrogen bonds.
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Affiliation(s)
- Ryutaro Souda
- Transmission Electron Microscopy Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
| | - Takashi Aizawa
- Center for Functional Sensor & Actuator, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Naoyuki Sugiyama
- Transmission Electron Microscopy Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan. and Toray Research Center Inc., 3-3-7 Sonoyama, Otsu, Shiga 520-8567, Japan
| | - Masaki Takeguchi
- Transmission Electron Microscopy Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
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Qiao C, Guo YR, Wang S, Jia Y, Wang CZ, Ho KM. Origin of short- and medium-range order in supercooled liquid Ge 3Sb 2Te 6 using ab initio molecular dynamics simulations. Phys Chem Chem Phys 2020; 22:9759-9766. [PMID: 32334427 DOI: 10.1039/d0cp00389a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phase-change materials such as Ge-Sb-Te compounds have attracted much attention due to their potential value in electrical data storage. In contrast to the amorphous and crystalline phases, supercooled liquids are far from being deeply understood despite their inevitable role in both amorphization and crystallization processes. To this end, we have studied the dynamics properties and structural characteristics of liquid and supercooled liquid Ge3Sb2Te6 during the fast cooling process. As the temperature decreases, chemical bonds become more homogeneous, but coordination numbers of Ge, Sb and Te atoms change very little. Meanwhile, the structural order of short-range configuration is obviously enhanced. Further studies suggest that Ge-centered, Sb-centered and Te-centered configurations change to the more ordered defective octahedrons mainly by adjusting the bond-angle relationship and bond length, rather than just by changing the coordination environment. It is the more ordered octahedrons that promote the formation of medium-range order. Our findings provide a deep insight into the origin of local structural order in supercooled liquid Ge3Sb2Te6, which is of great importance for the comprehensive understanding of amorphization and crystallization processes.
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Affiliation(s)
- Chong Qiao
- Shanghai Ultra-Precision Optical Manufacturing Engineering Center and Department of Optical Science and Engineering, Fudan University, Shanghai, 200433, China.
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Kooi BJ, Wuttig M. Chalcogenides by Design: Functionality through Metavalent Bonding and Confinement. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1908302. [PMID: 32243014 DOI: 10.1002/adma.201908302] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/03/2020] [Accepted: 02/03/2020] [Indexed: 05/27/2023]
Abstract
A unified picture of different application areas for incipient metals is presented. This unconventional material class includes several main-group chalcogenides, such as GeTe, PbTe, Sb2 Te3 , Bi2 Se3 , AgSbTe2 and Ge2 Sb2 Te5 . These compounds and related materials show a unique portfolio of physical properties. A novel map is discussed, which helps to explain these properties and separates the different fundamental bonding mechanisms (e.g., ionic, metallic, and covalent). The map also provides evidence for an unconventional, new bonding mechanism, coined metavalent bonding (MVB). Incipient metals, employing this bonding mechanism, also show a special bond breaking mechanism. MVB differs considerably from resonant bonding encountered in benzene or graphite. The concept of MVB is employed to explain the unique properties of materials utilizing it. Then, the link is made from fundamental insights to application-relevant properties, crucial for the use of these materials as thermoelectrics, phase change materials, topological insulators or as active photonic components. The close relationship of the materials' properties and their application potential provides optimization schemes for different applications. Finally, evidence will be presented that for metavalently bonded materials interesting effects arise in reduced dimensions. In particular, the consequences for the crystallization kinetics of thin films and nanoparticles will be discussed in detail.
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Affiliation(s)
- Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen, 9747 AG, the Netherlands
| | - Matthias Wuttig
- Institute of Physics IA, RWTH Aachen University, Aachen, 52074, Germany
- JARA-Institute: Energy-Efficient Information Technology (Green IT), Forschungszentrum Jülich GmbH, Jülich, 52428, Germany
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Shi L, Ying Z, Xu A, Cheng Y. Anomalous proton conduction behavior across a nanoporous two-dimensional conjugated aromatic polymer membrane. Phys Chem Chem Phys 2020; 22:2978-2985. [PMID: 31957775 DOI: 10.1039/c9cp06372b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We investigate aqueous proton penetration behavior across a newly synthesized nanoporous two-dimensional conjugated aromatic polymer (2D-CAP) membrane using extensive ReaxFF reactive molecular dynamics simulations. We found that the proton penetration energy barrier across 2D-CAP is twice as high as that of graphtetrayne, even though 2D-CAP exhibits a larger pore size. Detailed analysis indicates that the anomalous high proton conduction energy barrier of 2D-CAP originates from its unique atomic nanopore structure. The hydrogen atoms at the periphery of the 2D-CAP nanopores can form a stable local hydrogen bond network with water molecules inside or surrounding the nanopores. The mobility of water molecules involved in this local hydrogen bond network will be significantly lowered, and the proton transportation process across the nanopores will thus be impeded. Our results show that the proton penetration behavior across nanoporous 2D materials is influenced not only by the pore size, but also by the decorated atoms or functional groups at the pore edges. Hydrogen atoms at the periphery of nanopores with certain geometry can form a stable local hydrogen bond network with neighboring water molecules, further hampering the proton conductivity.
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Affiliation(s)
- Le Shi
- State key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Zhixuan Ying
- State key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Ao Xu
- School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yonghong Cheng
- State key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
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Roberts RC, Poling-Skutvik R, Conrad JC, Palmer JC. Tracer transport in attractive and repulsive supercooled liquids and glasses. J Chem Phys 2019; 151:194501. [DOI: 10.1063/1.5121851] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan C. Roberts
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
| | - Ryan Poling-Skutvik
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jacinta C. Conrad
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
| | - Jeremy C. Palmer
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204-4004, USA
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Bernasconi M. Atomistic Simulations of Phase Change Materials for Electronic Memories. INTERNATIONAL JOURNAL OF NANOSCIENCE 2019. [DOI: 10.1142/s0219581x19400829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We review our results on large-scale atomistic simulations of the phase change compound GeTe of interest for applications in nonvolatile electronic memories. The simulations are based on an interatomic potential with an accuracy close to that of the density functional theory (DFT). The potential was generated by fitting a DFT database by means of an artificial neural network method. This methodological advance allowed us to perform molecular dynamics simulations with several thousand atoms for several ns that provided useful insights on several properties of interest for the operation of phase change memories, including the crystallization kinetics, the dynamics of the supercooled liquid, the structural relaxation in the glass and the properties of nanowires.
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Affiliation(s)
- M. Bernasconi
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, Milano, Italy
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16
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Abstract
From intracellular freezing to cloud formation, the crystallization of water is ubiquitous and shapes life as we know it. A full comprehension of the ice nucleation process at the molecular scale remains elusive and we cannot predict where nucleation will occur. Using computational techniques we show that homogeneous nucleation in supercooled water happens in immobile liquid regions that emerge from heterogeneous dynamics. With this we link the topics of nucleation and dynamical heterogeneity and open ways to understand and control heterogeneous nucleation in solution, in confinement, or at interfaces via understanding their effects on liquid dynamics. When an ice crystal is born from liquid water, two key changes occur: (i) The molecules order and (ii) the mobility of the molecules drops as they adopt their lattice positions. Most research on ice nucleation (and crystallization in general) has focused on understanding the former with less attention paid to the latter. However, supercooled water exhibits fascinating and complex dynamical behavior, most notably dynamical heterogeneity (DH), a phenomenon where spatially separated domains of relatively mobile and immobile particles coexist. Strikingly, the microscopic connection between the DH of water and the nucleation of ice has yet to be unraveled directly at the molecular level. Here we tackle this issue via computer simulations which reveal that (i) ice nucleation occurs in low-mobility regions of the liquid, (ii) there is a dynamical incubation period in which the mobility of the molecules drops before any ice-like ordering, and (iii) ice-like clusters cause arrested dynamics in surrounding water molecules. With this we establish a clear connection between dynamics and nucleation. We anticipate that our findings will pave the way for the examination of the role of dynamical heterogeneities in heterogeneous and solution-based nucleation.
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17
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Gabardi S, Sosso GG, Behler J, Bernasconi M. Priming effects in the crystallization of the phase change compound GeTe from atomistic simulations. Faraday Discuss 2019; 213:287-301. [PMID: 30379974 DOI: 10.1039/c8fd00101d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Strategies to reduce the incubation time for crystal nucleation and thus the stochasticity of the set process are of relevance for the operation of phase change memories in ultra-scaled geometries. With these premises, in this work we investigate the crystallization kinetics of the phase change compound GeTe. We have performed large scale molecular dynamics simulations using an interatomic potential, generated previously from a neural network fitting of a database of ab initio energies. We have addressed the crystallization of models of amorphous GeTe annealed at different temperatures above the glass transition. The results on the distribution of subcritical nuclei and on the crystal growth velocity of postcritical ones are compared with our previous simulations of the supercooled liquid quenched from the melt. We find that a large population of subcritical nuclei can form at the lower temperatures where the nucleation rate is large. This population partially survives upon fast annealing, which leads to a dramatic reduction of the incubation time at high temperatures where the crystal growth velocity is maximal. This priming effect could be exploited to enhance the speed of the set process in phase change memories.
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Affiliation(s)
- Silvia Gabardi
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy.
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18
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Wei S, Evenson Z, Stolpe M, Lucas P, Angell CA. Breakdown of the Stokes-Einstein relation above the melting temperature in a liquid phase-change material. SCIENCE ADVANCES 2018; 4:eaat8632. [PMID: 30515453 PMCID: PMC6269161 DOI: 10.1126/sciadv.aat8632] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 10/26/2018] [Indexed: 05/17/2023]
Abstract
The dynamic properties of liquid phase-change materials (PCMs), such as viscosity η and the atomic self-diffusion coefficient D, play an essential role in the ultrafast phase switching behavior of novel nonvolatile phase-change memory applications. To connect η to D, the Stokes-Einstein relation (SER) is commonly assumed to be valid at high temperatures near or above the melting temperature T m and is often used for assessing liquid fragility (or crystal growth velocity) of technologically important PCMs. However, using quasi-elastic neutron scattering, we provide experimental evidence for a breakdown of the SER even at temperatures above T m in the high-atomic mobility state of a PCM, Ge1Sb2Te4. This implies that although viscosity may have strongly increased during cooling, diffusivity can remain high owing to early decoupling, being a favorable feature for the fast phase switching behavior of the high-fluidity PCM. We discuss the origin of the observation and propose the possible connection to a metal-semiconductor and fragile-strong transition hidden below T m.
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Affiliation(s)
- Shuai Wei
- I. Institute of Physics (IA), RWTH Aachen University, Aachen, Germany
| | - Zach Evenson
- Heinz Maier-Leibnitz Zentrum (MLZ) and Physik Department, Technische Universität München, Lichtenbergstrasse 1, 85747 Garching, Germany
| | - Moritz Stolpe
- Heraeus Holding GmbH, Heraeusstr.12-14, 63450 Hanau, Germany
- Chair of Metallic Materials, Saarland University, Campus C6.3, 66123 Saarbrücken, Germany
| | - Pierre Lucas
- Department of Materials Science and Engineering, University of Arizona, Tucson, AZ 85712, USA
| | - C. Austen Angell
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
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19
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Mocanu FC, Konstantinou K, Lee TH, Bernstein N, Deringer VL, Csányi G, Elliott SR. Modeling the Phase-Change Memory Material, Ge2Sb2Te5, with a Machine-Learned Interatomic Potential. J Phys Chem B 2018; 122:8998-9006. [DOI: 10.1021/acs.jpcb.8b06476] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Felix C. Mocanu
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Engineering Laboratory, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
| | | | - Tae Hoon Lee
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Noam Bernstein
- Center for Materials Physics and Technology, U.S. Naval Research Laboratory, Washington, District of Columbia 20375, United States
| | - Volker L. Deringer
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Engineering Laboratory, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
| | - Gábor Csányi
- Engineering Laboratory, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
| | - Stephen R. Elliott
- Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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20
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Sosso GC, Deringer VL, Elliott SR, Csányi G. Understanding the thermal properties of amorphous solids using machine-learning-based interatomic potentials. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1447107] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Gabriele C. Sosso
- Department of Chemistry and Centre for Scientific Computing, University of Warwick , Coventry, UK
| | - Volker L. Deringer
- Department of Engineering, University of Cambridge , Cambridge, UK
- Department of Chemistry, University of Cambridge , Cambridge, UK
| | | | - Gábor Csányi
- Department of Engineering, University of Cambridge , Cambridge, UK
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21
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Flores-Ruiz H, Micoulaut M. From elemental tellurium to Ge 2Sb 2Te 5 melts: High temperature dynamic and relaxation properties in relationship with the possible fragile to strong transition. J Chem Phys 2018; 148:034502. [PMID: 29352786 DOI: 10.1063/1.5013668] [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 investigate the dynamic properties of Ge-Sb-Te phase change melts using first principles molecular dynamics with a special emphasis on the effect of tellurium composition on melt dynamics. From structural models and trajectories established previously [H. Flores-Ruiz et al., Phys. Rev. B 92, 134205 (2015)], we calculate the diffusion coefficients for the different species, the activation energies for diffusion, the Van Hove correlation, and the intermediate scattering functions able to substantiate the dynamics and relaxation behavior of the liquids as a function of temperature and composition that is also compared to experiment whenever possible. We find that the diffusion is mostly Arrhenius-like and that the addition of Ge/Sb atoms leads to a global decrease of the jump probability and to an increase in activated dynamics for diffusion. Relaxation behavior is analyzed and used in order to evaluate the possibility of a fragile to strong transition that is evidenced from the calculated high fragility (M = 129) of Ge2Sb2Te5 at high temperatures.
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Affiliation(s)
- H Flores-Ruiz
- Laboratoire de Physique Théorique de la Matière Condensée, Paris Sorbonne Universités - UPMC, Boite 121, 4, Place Jussieu, 75252 Paris Cedex 05, France
| | - M Micoulaut
- Laboratoire de Physique Théorique de la Matière Condensée, Paris Sorbonne Universités - UPMC, Boite 121, 4, Place Jussieu, 75252 Paris Cedex 05, France
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22
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Micoulaut M, Bauchy M. Evidence for Anomalous Dynamic Heterogeneities in Isostatic Supercooled Liquids. PHYSICAL REVIEW LETTERS 2017; 118:145502. [PMID: 28430466 DOI: 10.1103/physrevlett.118.145502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Indexed: 06/07/2023]
Abstract
Upon cooling, the dynamics of supercooled liquids exhibits a growing transient spatial distribution of relaxation times that is known as dynamic heterogeneities. The relationship between this now well-established crucial feature of the glass transition and some underlying liquid properties remains challenging and elusive in many respects. Here we report on computer simulations of liquids with a changing network structure (densified silicates), and show that there is a deep and important link between the mechanical nature characterized by topological constraints and the spatial extent of such fluctuations. This is not only revealed by a maximum in the dynamic correlation length ξ_{4} for fluctuations when the liquid becomes isostatically rigid, but also by a contraction of the volume of relaxing structural correlations upon the onset of stressed rigidity.
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Affiliation(s)
- M Micoulaut
- Laboratoire de Physique Théorique de la Matière Condensée, Paris Sorbonne Universités-UPMC, 4 Place Jussieu, F-75252 Paris Cedex 05, France
| | - M Bauchy
- Department of Civil and Environmental Engineering, University of California, Los Angeles, California 90095-1593, USA
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23
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Qiu Y, Odendahl N, Hudait A, Mason R, Bertram AK, Paesani F, DeMott PJ, Molinero V. Ice Nucleation Efficiency of Hydroxylated Organic Surfaces Is Controlled by Their Structural Fluctuations and Mismatch to Ice. J Am Chem Soc 2017; 139:3052-3064. [PMID: 28135412 DOI: 10.1021/jacs.6b12210] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Heterogeneous nucleation of ice induced by organic materials is of fundamental importance for climate, biology, and industry. Among organic ice-nucleating surfaces, monolayers of long chain alcohols are particularly effective, while monolayers of fatty acids are significantly less so. As these monolayers expose to water hydroxyl groups with an order that resembles the one in the basal plane of ice, it was proposed that lattice matching between ice and the surface controls their ice-nucleating efficiency. Organic monolayers are soft materials and display significant fluctuations. It has been conjectured that these fluctuations assist in the nucleation of ice. Here we use molecular dynamic simulations and laboratory experiments to investigate the relationship between the structure and fluctuations of hydroxylated organic surfaces and the temperature at which they nucleate ice. We find that these surfaces order interfacial water to form domains with ice-like order that are the birthplace of ice. Both mismatch and fluctuations decrease the size of the preordered domains and monotonously decrease the ice freezing temperature. The simulations indicate that fluctuations depress the freezing efficiency of monolayers of alcohols or acids to half the value predicted from lattice mismatch alone. The model captures the experimental trend in freezing efficiencies as a function of chain length and predicts that alcohols have higher freezing efficiency than acids of the same chain length. These trends are mostly controlled by the modulation of the structural mismatch to ice. We use classical nucleation theory to show that the freezing efficiencies of the monolayers are directly related to their free energy of binding to ice. This study provides a general framework to relate the equilibrium thermodynamics of ice binding to a surface and the nonequilibrium ice freezing temperature and suggests that these could be predicted from the structure of interfacial water.
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Affiliation(s)
- Yuqing Qiu
- Department of Chemistry, The University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Nathan Odendahl
- Department of Chemistry, The University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Arpa Hudait
- Department of Chemistry, The University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Ryan Mason
- Department of Chemistry, University of British Columbia , Vancouver, British Columbia V6T 1Z1, Canada
| | - Allan K Bertram
- Department of Chemistry, University of British Columbia , Vancouver, British Columbia V6T 1Z1, Canada
| | - Francesco Paesani
- Department of Chemistry and Biochemistry, University of California, San Diego , La Jolla, California 92093, United States
| | - Paul J DeMott
- Department of Atmospheric Science, Colorado State University , Fort Collins, Colorado 80523-1371, United States
| | - Valeria Molinero
- Department of Chemistry, The University of Utah , 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
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24
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Yildirim C, Raty JY, Micoulaut M. Anomalous diffusion and non-monotonic relaxation processes in Ge-Se liquids. J Chem Phys 2016; 144:224503. [PMID: 27306014 DOI: 10.1063/1.4953077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We investigate the dynamical properties of liquid GexSe100-x as a function of Ge content by first-principles molecular dynamic simulations for a certain number of temperatures in the liquid state. The focus is set on ten compositions (where x ≤ 33%) encompassing the reported flexible to rigid and rigid to stressed-rigid transitions. We examine diffusion coefficients, diffusion activation energies, glassy relaxation behavior, and viscosity of these liquids from Van Hove correlation and intermediate scattering functions. At fixed temperature, all properties/functions exhibit an anomalous behavior with Ge content in the region 18%-22%, and provide a direct and quantitative link to the network rigidity.
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Affiliation(s)
- Can Yildirim
- Laboratoire de Physique Théorique de la Matière Condensée, Paris Sorbonne Universités, UPMC, 4, Place Jussieu, 75252 Paris Cedex 05, France
| | - Jean-Yves Raty
- Physique des Solides, Interfaces et Nanostructures et SESAME, B5 Université de Liège, B4000 Sart-Tilman, Belgium
| | - Matthieu Micoulaut
- Laboratoire de Physique Théorique de la Matière Condensée, Paris Sorbonne Universités, UPMC, 4, Place Jussieu, 75252 Paris Cedex 05, France
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25
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Micoulaut M. Relaxation and physical aging in network glasses: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:066504. [PMID: 27213928 DOI: 10.1088/0034-4885/79/6/066504] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recent progress in the description of glassy relaxation and aging are reviewed for the wide class of network-forming materials such as GeO2, Ge x Se1-x , silicates (SiO2-Na2O) or borates (B2O3-Li2O), all of which have an important usefulness in domestic, geological or optoelectronic applications. A brief introduction of the glass transition phenomenology is given, together with the salient features that are revealed both from theory and experiments. Standard experimental methods used for the characterization of the slowing down of the dynamics are reviewed. We then discuss the important role played by aspects of network topology and rigidity for the understanding of the relaxation of the glass transition, while also permitting analytical predictions of glass properties from simple and insightful models based on the network structure. We also emphasize the great utility of computer simulations which probe the dynamics at the molecular level, and permit the calculation of various structure-related functions in connection with glassy relaxation and the physics of aging which reveal the non-equilibrium nature of glasses. We discuss the notion of spatial variations of structure which leads to the concept of 'dynamic heterogeneities', and recent results in relation to this important topic for network glasses are also reviewed.
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Affiliation(s)
- Matthieu Micoulaut
- Paris Sorbonne Universités, LPTMC-UPMC, 4 place Jussieu, 75252 Paris cedex 05, France
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26
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Cuny J, Xie Y, Pickard CJ, Hassanali AA. Ab Initio Quality NMR Parameters in Solid-State Materials Using a High-Dimensional Neural-Network Representation. J Chem Theory Comput 2016; 12:765-73. [PMID: 26730889 DOI: 10.1021/acs.jctc.5b01006] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful experimental tools to probe the local atomic order of a wide range of solid-state compounds. However, due to the complexity of the related spectra, in particular for amorphous materials, their interpretation in terms of structural information is often challenging. These difficulties can be overcome by combining molecular dynamics simulations to generate realistic structural models with an ab initio evaluation of the corresponding chemical shift and quadrupolar coupling tensors. However, due to computational constraints, this approach is limited to relatively small system sizes which, for amorphous materials, prevents an adequate statistical sampling of the distribution of the local environments that is required to quantitatively describe the system. In this work, we present an approach to efficiently and accurately predict the NMR parameters of very large systems. This is achieved by using a high-dimensional neural-network representation of NMR parameters that are calculated using an ab initio formalism. To illustrate the potential of this approach, we applied this neural-network NMR (NN-NMR) method on the (17)O and (29)Si quadrupolar coupling and chemical shift parameters of various crystalline silica polymorphs and silica glasses. This approach is, in principal, general and has the potential to be applied to predict the NMR properties of various materials.
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Affiliation(s)
- Jérôme Cuny
- Laboratoire de Chimie et Physique Quantiques (LCPQ), Université de Toulouse [UPS] and CNRS , 118 Route de Narbonne, F-31062 Toulouse, France
| | - Yu Xie
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Chris J Pickard
- Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Ali A Hassanali
- Condensed Matter Physics Section, The Abdus Salaam International Center for Theoretical Physics , Strada Costiera 11, I-34151 Trieste, Trieste, Italy
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