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Gong M, Wu W, Xie D, Richter NA, Li Q, Zhang Y, Xue S, Zhang X, Wang J. First-principles calculations for understanding microstructures and mechanical properties of co-sputtered Al alloys. NANOSCALE 2021; 13:14987-15001. [PMID: 34533161 DOI: 10.1039/d1nr03333f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent experimental studies show that co-sputtering solutes with Al, together, can refine columnar grain size around few tens of nanometers and promote the formation and enhance the stability of planar defects such as stacking faults (SFs) and grain boundaries (GBs) in Al alloys. These crystal defects and fine columnar grains result in high strength, enhanced strain hardening and thermal stability of Al alloys. Using first-principles density-functional theory (DFT) calculations, we studied the role of eleven solutes in tailoring kinetics and energetics of adatoms and clusters on Al {111} surface, stable and unstable stacking fault energies, and kinetic energy barriers for the migration of defects. The calculations show that most solutes can effectively refine columnar grain size by decreasing the diffusivity of adatoms and surface clusters. These solutes do not necessarily decrease the stacking fault energy of Al alloys, but reduce the formation energy of faulted surface clusters and increase the energy barriers for the recovery of faulted surface clusters. Correspondingly, the formation of SFs is kinetically promoted during sputtering. Furthermore, solutes are segregated into the core of Shockley partial dislocations and play a pinning effect on SFs, SF arrays and twin boundaries, enhancing the thermal stability of these crystal defects. These findings provide insights into the design of high-strength Al alloys for high-temperature applications.
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Affiliation(s)
- Mingyu Gong
- Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
| | - Wenqian Wu
- Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
| | - Dongyue Xie
- Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
| | - Nicholas A Richter
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Qiang Li
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Yifan Zhang
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Sichuang Xue
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Xinghang Zhang
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Jian Wang
- Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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Mahakrishnan S, Chakraborty S, Vijay A. Anomalies in the equilibrium and nonequilibrium properties of correlated ions in complex molecular environments. Phys Rev E 2018; 96:052133. [PMID: 29347760 DOI: 10.1103/physreve.96.052133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Indexed: 11/07/2022]
Abstract
Emergent statistical attributes, and therefore the equations of state, of an assembly of interacting charge carriers embedded within a complex molecular environment frequently exhibit a variety of anomalies, particularly in the high-density (equivalently, the concentration) regime, which are not well understood, because they do not fall under the low-concentration phenomenologies of Debye-Hückel-Onsager and Poisson-Nernst-Planck, including their variants. To go beyond, we here use physical concepts and mathematical tools from quantum scattering theory, transport theory with the Stosszahlansatz of Boltzmann, and classical electrodynamics (Lorentz gauge) and obtain analytical expressions both for the average and the frequency-wave vector-dependent longitudinal and transverse current densities, diffusion coefficient, and the charge density, and therefore the analytical expressions for (a) the chemical potential, activity coefficient, and the equivalent conductivity for strong electrolytes and (b) the current-voltage characteristics for ion-transport processes in complex molecular environments. Using a method analogous to the notion of Debye length and thence the electrical double layer, we here identify a pair of characteristic length scales (longitudinal and the transverse), which, being wave vector and frequency dependent, manifestly exhibit nontrivial fluctuations in space-time. As a unifying theme, we advance a quantity (inverse length dimension), g_{scat}^{(a)}, which embodies all dynamical interactions, through various quantum scattering lengths, relevant to molecular species a, and the analytical behavior which helps us to rationalize the properties of strong electrolytes, including anomalies, in all concentration regimes. As an example, the behavior of g_{scat}^{(a)} in the high-concentration regime explains the anomalous increase of the Debye length with concentration, as seen in a recent experiment on electrolyte solutions. We also put forth an extension of the standard diffusion equation, which manifestly incorporates the effects arising from the underlying microscopic collisions among constituent molecular species. Furthermore, we show a nontrivial connection between the current-voltage characteristics of electrolyte solutions and the Landauer's approach to electrical conduction in mesoscopic solids and thereby establish a definite conceptual bridge between the two disjoint subjects. For numerical insight, we present results on the aqueous solution of KCl as an example of strong electrolyte, and the transport (conduction as well as diffusion) of K^{+} ions in water, as an example of ion transport across the voltage-gated channels in biological cells.
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Affiliation(s)
- Sathiya Mahakrishnan
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Subrata Chakraborty
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - Amrendra Vijay
- Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India
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Mahakrishnan S, Chakraborty S, Vijay A. Normal and Anomalous Diffusion: An Analytical Study Based on Quantum Collision Dynamics and Boltzmann Transport Theory. J Phys Chem B 2016; 120:9608-20. [PMID: 27552086 DOI: 10.1021/acs.jpcb.6b06380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diffusion, an emergent nonequilibrium transport phenomenon, is a nontrivial manifestation of the correlation between the microscopic dynamics of individual molecules and their statistical behavior observed in experiments. We present a thorough investigation of this viewpoint using the mathematical tools of quantum scattering, within the framework of Boltzmann transport theory. In particular, we ask: (a) How and when does a normal diffusive transport become anomalous? (b) What physical attribute of the system is conceptually useful to faithfully rationalize large variations in the coefficient of normal diffusion, observed particularly within the dynamical environment of biological cells? To characterize the diffusive transport, we introduce, analogous to continuous phase transitions, the curvature of the mean square displacement as an order parameter and use the notion of quantum scattering length, which measures the effective interactions between the diffusing molecules and the surrounding, to define a tuning variable, η. We show that the curvature signature conveniently differentiates the normal diffusion regime from the superdiffusion and subdiffusion regimes and the critical point, η = ηc, unambiguously determines the coefficient of normal diffusion. To solve the Boltzmann equation analytically, we use a quantum mechanical expression for the scattering amplitude in the Boltzmann collision term and obtain a general expression for the effective linear collision operator, useful for a variety of transport studies. We also demonstrate that the scattering length is a useful dynamical characteristic to rationalize experimental observations on diffusive transport in complex systems. We assess the numerical accuracy of the present work with representative experimental results on diffusion processes in biological systems. Furthermore, we advance the idea of temperature-dependent effective voltage (of the order of 1 μV or less in a biological environment, for example) as a dynamical cause of the perpetual molecular movement, which eventually manifests as an ordered motion, called the diffusion.
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Affiliation(s)
- Sathiya Mahakrishnan
- Department of Chemistry, Indian Institute of Technology Madras , Chennai 600036, India
| | - Subrata Chakraborty
- Department of Chemistry, Indian Institute of Technology Madras , Chennai 600036, India
| | - Amrendra Vijay
- Department of Chemistry, Indian Institute of Technology Madras , Chennai 600036, India
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Walen H, Liu DJ, Oh J, Lim H, Evans JW, Kim Y, Thiel PA. Self-organization of S adatoms on Au(111): √3R30° rows at low coverage. J Chem Phys 2015; 143:014704. [DOI: 10.1063/1.4922929] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Holly Walen
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Da-Jiang Liu
- Ames Laboratory of the USDOE, Ames, Iowa 50011, USA
| | - Junepyo Oh
- RIKEN Surface and Interface Science Laboratory, Wako, Saitama 351-0198, Japan
| | - Hyunseob Lim
- RIKEN Surface and Interface Science Laboratory, Wako, Saitama 351-0198, Japan
| | - J. W. Evans
- Ames Laboratory of the USDOE, Ames, Iowa 50011, USA
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Yousoo Kim
- RIKEN Surface and Interface Science Laboratory, Wako, Saitama 351-0198, Japan
| | - P. A. Thiel
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
- Ames Laboratory of the USDOE, Ames, Iowa 50011, USA
- Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011, USA
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Ranade PS, Chrzan DC. Nucleation of Islands During Epitaxial Growth: Influence of a Second Species. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-528-25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe theory of the nucleation and growth of islands is maturing rapidly. This advance is driven by the increased availability of experimental data, as well as the need for better control over growth processes. Recently, a number of authors have studied the effects of introducing a second species onto the surface in order to influence the ultimate growth morphology. In some situations, the addition of a second species results in a signficant change (approximately a factor of 1000) in the nucleated island density. The origin of this increase in density has been linked to the anomalous diffusion induced by the presence of the additional species of atoms. In the current paper, this dependence is explored further. In particular, earlier work focused on nucleation and growth in the regime in which the second species is essentially immobile. This constraint is relaxed here, and the subsequent model studied through application of a self-consistent mean-field theory. Predictions for the total island density are presented.
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Anomalous Stochastic Processes in the Fractional Dynamics Framework: Fokker-Planck Equation, Dispersive Transport, and Non-Exponential Relaxation. ADVANCES IN CHEMICAL PHYSICS 2007. [DOI: 10.1002/9780470141762.ch3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Surface-phase equilibria in MBE of strained In1-xGaxAs heteroepitaxcial layers. E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2006. [DOI: 10.1380/ejssnt.2006.53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Mazzitello K, Aldao CM, Mártin HO. Effects of the sticking probability on the scaling of the island density in a point island model. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:066120. [PMID: 11415186 DOI: 10.1103/physreve.63.066120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2000] [Indexed: 05/23/2023]
Abstract
The behavior of the island density exponent chi for a model of deposition, nucleation, and aggregation of particles, forming point islands with a sticking probability p in one dimension, is analyzed. Using Monte Carlo simulation we found that chi depends on p. For p=1 we obtain chi congruent with 1/4, the well-known result for perfect sticking and one-dimensional diffusion. Interestingly, as p is decreased, chi adopts higher values. Possible reasons for this behavior are addressed. The universal result for a one-dimensional diffusion, chi=1/4, is expected to be recovered, for all p, only in the asymptotic regime.
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Affiliation(s)
- K Mazzitello
- Physics Department, School of Exact and Natural Sciences, Universidad Nacional de Mar del Plata, Deán Funes 3350, 7600 Mar del Plata, Argentina
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Liu DJ, Evans JW. Surface diffusion in mixed overlayers with superlattice ordering: Percolative transport around obstacles and along domain boundaries. J Chem Phys 2000. [DOI: 10.1063/1.1322356] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Schulzky C, Essex C, Davison M, Franz A, Hoffmann KH. The similarity group and anomalous diffusion equations. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0305-4470/33/31/305] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chapter 13 Density-functional theory of epitaxial growth of metals. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1571-0785(97)80016-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Wu JQ, Zhao WB, Chen J, Wu K, Wang ZJ, Zhang JL, Li CY, Yin DL, Gu ZN, Jin ZX, Zhou XH. Nonlinear resistivity and critical behavior of metal-overlayer percolation systems on epitaxial fullerene films. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:9840-9845. [PMID: 9984718 DOI: 10.1103/physrevb.54.9840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Fiorentini V, Fois D, Oppo S. Inhibited Al Diffusion and Growth Roughening of Ga-Coated Al(100). PHYSICAL REVIEW LETTERS 1996; 77:695-698. [PMID: 10062879 DOI: 10.1103/physrevlett.77.695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Ebinger HD, Jänsch HJ, Polenz C, Polivka B, Preyss W, Saier V, Veith R, Fick D. NMR observation of diffusion barriers for lithium adsorbed on Ru(001). PHYSICAL REVIEW LETTERS 1996; 76:656-659. [PMID: 10061514 DOI: 10.1103/physrevlett.76.656] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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