Thermodynamic and fractal geometric aspects of ion-solid interactions
TL;DR: In this article, a fractal geometry approach to spike formation is presented, based on an idealized collision cascade constructed from the inverse power potential V(r) √ r−1/m (0).
About: This article is published in Materials Science Reports.The article was published on 1990-01-01. It has received 229 citations till now. The article focuses on the topics: Collision cascade & Ion.
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TL;DR: A review of different mechanisms that have been proposed and how they fit together in terms of the kinetic regimes in which they dominate is provided in this paper, with a comparison between theory and experiment is used to highlight strengths and weaknesses in their understanding.
Abstract: When collimated beams of low energy ions are used to bombard materials, the surface often develops a periodic pattern or “ripple” structure. Different types of patterns are observed to develop under different conditions, with characteristic features that depend on the substrate material, the ion beam parameters, and the processing conditions. Because the patterns develop spontaneously, without applying any external mask or template, their formation is the expression of a dynamic balance among fundamental surface kinetic processes, e.g., erosion of material from the surface, ion-induced defect creation, and defect-mediated evolution of the surface morphology. In recent years, a comprehensive picture of the different kinetic mechanisms that control the different types of patterns that form has begun to emerge. In this article, we provide a review of different mechanisms that have been proposed and how they fit together in terms of the kinetic regimes in which they dominate. These are grouped into regions of behavior dominated by the directionality of the ion beam, the crystallinity of the surface, the barriers to surface roughening, and nonlinear effects. In sections devoted to each type of behavior, we relate experimental observations of patterning in these regimes to predictions of continuum models and to computer simulations. A comparison between theory and experiment is used to highlight strengths and weaknesses in our understanding. We also discuss the patterning behavior that falls outside the scope of the current understanding and opportunities for advancement.
435 citations
TL;DR: A review of ion beam modifications at various solids, thin films, and multilayered systems covering wider energy ranges including the older basic concepts is given in this paper. But the results reveal that the ion-solid interaction physics provides a unique way for controlling the produced defects of the desired type at a desired location.
242 citations
TL;DR: In this article, the basics of the ion mixing phenomenon are described and discussed, and the process is examined by considering only ballistic and kinematic effects associated with collisions between projectile and target atoms, and how collision cascades and the evolution of dense energy spikes affect the mixing process.
Abstract: In this review we shall describe and discuss the basics of the ion mixing phenomenon. First, the process is examined by considering only ballistic and kinematic effects associated with collisions between projectile and target atoms. We shall examine how collision cascades and the evolution of dense energy spikes affect the mixing process. We then show how material properties, such as heat of mixing and cohesive energy, influence the mixing process. These properties lead to the physical basis for the occurrence of temperature-independent and temperature-dependent mixing regimes. Finally, we shall examine the phase formation possibilities in the ion-reacted layer, and how irradiation conditions and various material properties can influence the final structure that forms.
155 citations
TL;DR: The generalized Lindemann melting hypothesis as mentioned in this paper assumes that the melting of a defective crystal occurs when the sum of the static and thermal mean-square displacements reaches a critical fraction of the interatomic spacing, which is equivalent to a disorder-induced softening of the shear modulus.
Abstract: Publisher Summary This chapter focuses on the relationship between melting and solid-state amorphization It discusses that amorphization is a disorder-driven melting process, occurring below the glass transition temperature, and that a unified approach to heating- and disorder-induced melting is found in the generalized version of the Lindemann melting hypothesis This hypothesis assumes that the melting of a defective crystal occurs when the sum of the static and thermal mean-square displacements reaches a critical fraction of the interatomic spacing, which was shown to be equivalent to a generalized T o -concept resulting from a disorder-induced softening of the shear modulus Comparisons with available experimental data and with the predictions of microscopic defect-mediated melting models were made to establish the validity of the generalized Lindemann melting criterion The chapter explores that the disorder-induced melting concept provides a new thermodynamic approach to understand other materials problems, including brittle fracture and stress-corrosion cracking Stress-corrosion cracking is viewed as premelting of high-energy grain boundaries, because of the combined effects of applied stresses and the segregation of insoluble impurities in lowering the melting temperature of grain boundaries to the ambient temperature Stress-induced melting may also occur in the vicinity of moving crack tips However, as revealed by atomistic simulations, the local melting is a transient phenomenon at elevated temperatures and, hence it is observable only at temperatures below the glass transition temperature where the liquid phase persists indefinitely as a glass
133 citations
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Book•
01 Jan 1982
TL;DR: This book is a blend of erudition, popularization, and exposition, and the illustrations include many superb examples of computer graphics that are works of art in their own right.
Abstract: "...a blend of erudition (fascinating and sometimes obscure historical minutiae abound), popularization (mathematical rigor is relegated to appendices) and exposition (the reader need have little knowledge of the fields involved) ...and the illustrations include many superb examples of computer graphics that are works of art in their own right." Nature
24,199 citations
23,110 citations
Book•
01 Jan 1985
TL;DR: In this paper, a scaling solution for the Bethe lattice is proposed for cluster numbers and a scaling assumption for cluster number scaling assumptions for cluster radius and fractal dimension is proposed.
Abstract: Preface to the Second Edition Preface to the First Edition Introduction: Forest Fires, Fractal Oil Fields, and Diffusion What is percolation? Forest fires Oil fields and fractals Diffusion in disordered media Coming attractions Further reading Cluster Numbers The truth about percolation Exact solution in one dimension Small clusters and animals in d dimensions Exact solution for the Bethe lattice Towards a scaling solution for cluster numbers Scaling assumptions for cluster numbers Numerical tests Cluster numbers away from Pc Further reading Cluster Structure Is the cluster perimeter a real perimeter? Cluster radius and fractal dimension Another view on scaling The infinite cluster at the threshold Further reading Finite-size Scaling and the Renormalization Group Finite-size scaling Small cell renormalization Scaling revisited Large cell and Monte Carlo renormalization Connection to geometry Further reading Conductivity and Related Properties Conductivity of random resistor networks Internal structure of the infinite cluster Multitude of fractal dimensions on the incipient infinite cluster Multifractals Fractal models Renormalization group for internal cluster structure Continuum percolation, Swiss-cheese models and broad distributions Elastic networks Further reading Walks, Dynamics and Quantum Effects Ants in the labyrinth Probability distributions Fractons and superlocalization Hulls and external accessible perimeters Diffusion fronts Invasion percolation Further reading Application to Thermal Phase Transitions Statistical physics and the Ising model Dilute magnets at low temperatures History of droplet descriptions for fluids Droplet definition for the Ising model in zero field The trouble with Kertesz Applications Dilute magnets at finite temperatures Spin glasses Further reading Summary Numerical Techniques
9,830 citations
01 Jul 1984
TL;DR: A blend of erudition (fascinating and sometimes obscure historical minutiae abound), popularization (mathematical rigor is relegated to appendices) and exposition (the reader need have little knowledge of the fields involved) is presented in this article.
Abstract: "...a blend of erudition (fascinating and sometimes obscure historical minutiae abound), popularization (mathematical rigor is relegated to appendices) and exposition (the reader need have little knowledge of the fields involved) ...and the illustrations include many superb examples of computer graphics that are works of art in their own right." Nature
7,560 citations