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Liu C, Yip WS, To S, Chen B, Xu J. Numerical Investigation on the Effects of Grain Size and Grinding Depth on Nano-Grinding of Cadmium Telluride Using Molecular Dynamics Simulation. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2670. [PMID: 37836311 PMCID: PMC10574599 DOI: 10.3390/nano13192670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/24/2023] [Accepted: 08/25/2023] [Indexed: 10/15/2023]
Abstract
Cadmium telluride (CdTe) is known as an important semiconductor material with favorable physical properties. However, as a soft-brittle material, the fabrication of high-quality surfaces on CdTe is quite challenging. To improve the fundamental understanding of the nanoscale deformation mechanisms of CdTe, in this paper, MD simulation was performed to explore the nano-grinding process of CdTe with consideration of the effects of grain size and grinding depth. The simulation results indicate that during nano-grinding, the dominant grinding mechanism could switch from elastic deformation to ploughing, and then cutting as the grinding depth increases. It was observed that the critical relative grain sharpness (RGS) for the transition from ploughing to cutting is greatly influenced by the grain size. Furthermore, as the grinding depth increases, the dominant subsurface damage mechanism could switch from surface friction into slip motion along the <110> directions. Meanwhile, as the grain size increases, less friction-induced damage is generated in the subsurface workpiece, and more dislocations are formed near the machined groove. Moreover, regardless of the grain size, it was observed that the generation of dislocation is more apparent as the dominant grinding mechanism becomes ploughing and cutting.
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Affiliation(s)
- Changlin Liu
- State Key Laboratory of Ultra-Recision Machining Technology, The Hong Kong Polytechnic University, Hong Kong 999077, China; (C.L.); (W.S.Y.)
| | - Wai Sze Yip
- State Key Laboratory of Ultra-Recision Machining Technology, The Hong Kong Polytechnic University, Hong Kong 999077, China; (C.L.); (W.S.Y.)
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518000, China
| | - Suet To
- State Key Laboratory of Ultra-Recision Machining Technology, The Hong Kong Polytechnic University, Hong Kong 999077, China; (C.L.); (W.S.Y.)
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518000, China
| | - Bolong Chen
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China;
| | - Jianfeng Xu
- State Key Laboratory of Intelligent Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China;
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Yokoi T, Adachi K, Iwase S, Matsunaga K. Accurate prediction of grain boundary structures and energetics in CdTe: a machine-learning potential approach. Phys Chem Chem Phys 2021; 24:1620-1629. [PMID: 34951419 DOI: 10.1039/d1cp04329c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To accurately predict grain boundary (GB) atomic structures and their energetics in CdTe, the present study constructs an artificial-neural-network (ANN) interatomic potential. To cover a wide range of atomic environments, large amounts of density functional theory (DFT) data are used as a training dataset including point defects, surfaces and GBs. Structural relaxation combined with the trained ANN potential is applied to symmetric tilt and twist GBs, many of which are not included in the training dataset. The relative stability of the relaxed structures and their GB energies are then evaluated with the DFT level. The ANN potential is found to accurately predict low-energy structures and their energetics with reasonable accuracy with respect to DFT results, while conventional empirical potentials critically fail to find low-energy structures. The present study also provides a way to further improve the transferability of the ANN potential to more complicated GBs, using only low-Σ GBs as training datasets. Such improvement will offer a way to accurately predict atomic structures of general GBs within practical computational cost.
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Affiliation(s)
- Tatsuya Yokoi
- Department of Materials Physics, Nagoya University, Nagoya 464-8603, Japan.
| | - Kosuke Adachi
- Department of Materials Physics, Nagoya University, Nagoya 464-8603, Japan.
| | - Sayuri Iwase
- Department of Materials Physics, Nagoya University, Nagoya 464-8603, Japan.
| | - Katsuyuki Matsunaga
- Department of Materials Physics, Nagoya University, Nagoya 464-8603, Japan. .,Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya, 456-8587, Japan
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3
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Mińkowski M, Hummer K, Dellago C. Cation interstitial diffusion in lead telluride and cadmium telluride studied by means of neural network potential based molecular dynamics simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:015901. [PMID: 33043897 DOI: 10.1088/1361-648x/abb740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Using a recently developed approach to represent ab initio based force fields by a neural network potential, we perform molecular dynamics simulations of lead telluride and cadmium telluride crystals. In particular, we study the diffusion of a single cation interstitial in these two systems. Our simulations indicate that the interstitials migrate via two distinct mechanisms: through hops between interstitial sites and through exchanges with lattice atoms. We extract activation energies for both of these mechanisms and show how the temperature dependence of the total diffusion coefficient deviates from Arrhenius behaviour. The accuracy of the neural network approach is estimated by comparing the results for three different independently trained potentials.
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Affiliation(s)
- Marcin Mińkowski
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Kerstin Hummer
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
| | - Christoph Dellago
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
- Vienna Research Platform on Accelerating Photoreaction Discovery, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
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4
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Fijan D, Wilson M. Liquid state anomalies and the relationship to the crystalline phase diagram. Phys Rev E 2019; 99:010103. [PMID: 30780346 DOI: 10.1103/physreve.99.010103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Indexed: 06/09/2023]
Abstract
A relationship between the observation of a density anomaly and the underlying crystalline phase diagram is demonstrated. The crystal phase diagram and temperature of maximum density (TMD) lines are calculated over a range of parameter space using a Stillinger-Weber potential. Relationships between the loci of density maxima in the PT plane for the liquid state and the underlying crystalline phase diagram are investigated. Two key potential parameters are systematically varied in order to control the balance between the model two- and three-body interaction terms, and the relative effects of varying the potential parameters analyzed. The respective TMD lines diverge at extreme values with one set of lines showing a reentrant behavior. For each parameter set the TMD lines are extrapolated to T=0K. The corresponding pressures are related to the crystalline phase diagram and are found to lie on or near specific crystal-crystal coexistence lines for a wide range of potential parameters. The density anomaly is observed to vanish corresponding to regions in the crystal phase diagram which lack crystal-crystal coexistence lines potentially offering a new interpretation for the emergence of anomalous behavior.
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Affiliation(s)
- Domagoj Fijan
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Mark Wilson
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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5
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Kelley AM. Comparison of three empirical force fields for phonon calculations in CdSe quantum dots. J Chem Phys 2016; 144:214702. [DOI: 10.1063/1.4952990] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Anne Myers Kelley
- Chemistry and Chemical Biology, University of California, Merced, 5200 North Lake Road, Merced, California 95343, USA
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6
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Atomic and electronic structure of Lomer dislocations at CdTe bicrystal interface. Sci Rep 2016; 6:27009. [PMID: 27255415 PMCID: PMC4891715 DOI: 10.1038/srep27009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/12/2016] [Indexed: 12/01/2022] Open
Abstract
Extended defects are of considerable importance in determining the electronic properties of semiconductors, especially in photovoltaics (PVs), due to their effects on electron-hole recombination. We employ model systems to study the effects of dislocations in CdTe by constructing grain boundaries using wafer bonding. Atomic-resolution scanning transmission electron microscopy (STEM) of a [1–10]/(110) 4.8° tilt grain boundary reveals that the interface is composed of three distinct types of Lomer dislocations. Geometrical phase analysis is used to map strain fields, while STEM and density functional theory (DFT) modeling determine the atomic structure at the interface. The electronic structure of the dislocation cores calculated using DFT shows significant mid-gap states and different charge-channeling tendencies. Cl-doping is shown to reduce the midgap states, while maintaining the charge separation effects. This report offers novel avenues for exploring grain boundary effects in CdTe-based solar cells by fabricating controlled bicrystal interfaces and systematic atomic-scale analysis.
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Shen K, Bai Z, Deng Y, Yang R, Wang D, Li Q, Wang D. High efficiency CdTe solar cells with a through-thickness polycrystalline CdTe thin film. RSC Adv 2016. [DOI: 10.1039/c6ra07201a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
CdTe preferential growth with through-thickness grains has been achieved. A crystalline growth mechanism assisted by an oxide liquid phase is proposed.
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Affiliation(s)
- Kai Shen
- Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei
- People's Republic of China
- Department of Electronic Engineering
| | - Zhizhong Bai
- Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei
- People's Republic of China
| | - Yi Deng
- School of Electronic and Information Engineering
- Hankou University
- Wuhan 430212
- People's Republic of China
| | - Ruilong Yang
- Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei
- People's Republic of China
| | - Dezhao Wang
- Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei
- People's Republic of China
| | - Qiang Li
- Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei
- People's Republic of China
| | - Deliang Wang
- Hefei National Laboratory for Physical Sciences at the Microscale
- University of Science and Technology of China
- Hefei
- People's Republic of China
- CAS Key Laboratory of Energy Conversion Materials
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8
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Hu XL, Ciaglia R, Pietrucci F, Gallet GA, Andreoni W. DFT-Derived Reactive Potentials for the Simulation of Activated Processes: the Case of CdTe and CdTe:S. J Phys Chem B 2014; 118:6531-8. [DOI: 10.1021/jp412808m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiao Liang Hu
- Institut
de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Riccardo Ciaglia
- Centre
Européen de Calcul Atomique et Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Fabio Pietrucci
- Institut
de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Centre
Européen de Calcul Atomique et Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Grégoire A. Gallet
- Institut
de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Centre
Européen de Calcul Atomique et Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Wanda Andreoni
- Institut
de Théorie des Phénomènes Physiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Centre
Européen de Calcul Atomique et Moléculaire, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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9
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Abstract
Global optimization for molecular clusters can be significantly more difficult than for atomic clusters because of the coupling between orientational and translational degrees of freedom. A coarse-grained representation of the potential can reduce the complexity of this problem, while retaining the essential features of the intermolecular interactions. In this study, we use a basin-hopping algorithm to locate putative global minima for clusters of coarse-grained water molecules modeled using a monatomic water potential for cluster sizes 3 ≤ N ≤ 55. We characterize these structures and identify structural trends using ideas from graph theory. The agreement with atomistic results and experiment is rather patchy, which we attribute to the tetrahedral bias in the three-body potential that results in too few nearest neighbor contacts and premature emergence of bulk-like structure. In spite of this issue, the results offer further useful insight into the relationship between the structure of clusters and bulk phases, and the mathematical form of a widely used model potential.
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Affiliation(s)
- James D Farrell
- University Chemical Laboratories , Lensfield Road, Cambridge CB2 1EW, United Kingdom
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10
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Zhou XW, Ward DK, Wong BM, Doty FP. Melt-growth dynamics in CdTe crystals. PHYSICAL REVIEW LETTERS 2012; 108:245503. [PMID: 23004290 DOI: 10.1103/physrevlett.108.245503] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Indexed: 06/01/2023]
Abstract
We use a new, quantum-mechanics-based bond-order potential (BOP) to reveal melt growth dynamics and fine scale defect formation mechanisms in CdTe crystals. Previous molecular dynamics simulations of semiconductors have shown qualitatively incorrect behavior due to the lack of an interatomic potential capable of predicting both crystalline growth and property trends of many transitional structures encountered during the melt→crystal transformation. Here, we demonstrate successful molecular dynamics simulations of melt growth in CdTe using a BOP that significantly improves over other potentials on property trends of different phases. Our simulations result in a detailed understanding of defect formation during the melt growth process. Equally important, we show that the new BOP enables defect formation mechanisms to be studied at a scale level comparable to empirical molecular dynamics simulation methods with a fidelity level approaching quantum-mechanical methods.
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Affiliation(s)
- X W Zhou
- Sandia National Laboratories, Livermore, California 94550, USA.
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11
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Ward DK, Zhou XW, Wong BM, Doty FP, Zimmerman JA. Accuracy of existing atomic potentials for the CdTe semiconductor compound. J Chem Phys 2011; 134:244703. [DOI: 10.1063/1.3596746] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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12
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Larini L, Lu L, Voth GA. The multiscale coarse-graining method. VI. Implementation of three-body coarse-grained potentials. J Chem Phys 2010; 132:164107. [PMID: 20441258 DOI: 10.1063/1.3394863] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Many methodologies have been proposed to build reliable and computationally fast coarse-grained potentials. Typically, these force fields rely on the assumption that the relevant properties of the system under examination can be reproduced using a pairwise decomposition of the effective coarse-grained forces. In this work it is shown that an extension of the multiscale coarse-graining technique can be employed to parameterize a certain class of two-body and three-body force fields from atomistic configurations. The use of explicit three-body potentials greatly improves the results over the more commonly used two-body approximation. The method proposed here is applied to develop accurate one-site coarse-grained water models.
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Affiliation(s)
- Luca Larini
- Department of Chemistry and Center for Biophysical Modeling and Simulation, University of Utah, 315 S 1400 E, Salt Lake City, Utah 84112, USA
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13
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Angelo JE, Mills MJ. Investigations of the misfit dislocation structure at a CdTe(001)/ga As(001) interface using Stillinger-Weber potentials and high-resolution transmission electron microscopy. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01418619508243790] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Scheerschmidt K, Conrad D, Kirmse H, Schneider R, Neumann W. Electron microscope characterization of CdSe/ZnSe quantum dots based on molecular dynamics structure relaxations. Ultramicroscopy 2000; 81:289-300. [PMID: 10782652 DOI: 10.1016/s0304-3991(99)00185-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Molecular dynamics simulations using empirical potentials are applied to characterize the structure, the energy relaxation and the stability of pyramidal-shaped quantum dots in the CdSe/ZnSe system. The relaxed structure models are used for a reliable interpretation of electron microscope investigations to analyze the size, the shape and the strain fields of the quantum dots. Though the elastic strains modify the electron microsope image contrast by creating virtual truncations of the pyramids or additional black-white lobes, optimum imaging conditions chosen will reveal the shape and the size of the dots.
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Affiliation(s)
- K Scheerschmidt
- Max Planck Institute of Microstructure Physics, Halle, Germany.
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Kirmse H, Schneider R, Scheerschmidt K, Conrad D, Neumann W. TEM characterization of self-organized CdSe/ZnSe quantum dots. J Microsc 1999; 194:183-191. [PMID: 10320552 DOI: 10.1046/j.1365-2818.1999.00452.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CdSe quantum dots (QDs) grown on ZnSe were investigated by various transmission electron microscopy (TEM) techniques including diffraction contrast imaging, high-resolution and analytical transmission electron microscopy both of plan-view as well as cross-section specimens. The size of the QDs ranges from about 5-50 nm, where from the contrast features in plan-view imaging two classes can be differentiated. In the features of the smaller dots there is no inner fine structure resolvable. The larger ones exhibit contrast features of fourfold symmetry as expected for pyramid-like islands. Corresponding simulations of diffraction contrast images of truncated CdSe pyramids with the edges of the basal plane orientated parallel to <100> are in relatively good agreement with this assumption. In TEM diffraction contrast imaging of cross-section samples the locations of the quantum dots are visualized by additional dark contrast features. The QDs have a distinct larger extension in growth direction compared to the almost uniformly thick CdSe wetting layer. The presence of the CdSe QDs was also confirmed by energy-dispersive X-ray spectroscopy.
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Affiliation(s)
- H Kirmse
- Humboldt-Universität zu Berlin, Institut für Physik, Lehrstuhl für Kristallographie, Invalidenstrabetae 110, D-10115 Berlin, Germany
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Wang ZQ, Stroud D. Monte Carlo study of liquid GaAs: Bulk and surface properties. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:5353-5356. [PMID: 9996107 DOI: 10.1103/physrevb.42.5353] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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