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T. Diaz de la Rubia

Bio: T. Diaz de la Rubia is an academic researcher from Lawrence Livermore National Laboratory. The author has contributed to research in topics: Vacancy defect & Kinetic Monte Carlo. The author has an hindex of 43, co-authored 144 publications receiving 7703 citations. Previous affiliations of T. Diaz de la Rubia include University at Albany, SUNY & Argonne National Laboratory.


Papers
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Journal ArticleDOI
TL;DR: A comprehensive review of the state-of-the-art of radiation effects in crystalline ceramics that may be used for the immobilization of high-level nuclear waste and plutonium is provided in this article.
Abstract: This review provides a comprehensive evaluation of the state-of-knowledge of radiation effects in crystalline ceramics that may be used for the immobilization of high-level nuclear waste and plutonium. The current understanding of radiation damage processes, defect generation, microstructure development, theoretical methods, and experimental methods are reviewed. Fundamental scientific and technological issues that offer opportunities for research are identified. The most important issue is the need for an understanding of the radiation-induced structural changes at the atomic, microscopic, and macroscopic levels, and the effect of these changes on the release rates of radionuclides during corrosion.

834 citations

Journal ArticleDOI
TL;DR: In this article, a comparative molecular dynamics simulation study of collision cascades in two elemental semiconductors and five fcc metals is performed to elucidate how different material characteristics affect primary defect production during ion irradiation.
Abstract: A comparative molecular dynamics simulation study of collision cascades in two elemental semiconductors and five fcc metals is performed to elucidate how different material characteristics affect primary defect production during ion irradiation. By using simulations of full 400 eV-10 keV collision cascades and contrasting the results on different materials with each other, we probe the effect of the mass, melting temperature, material strength, and crystal structure on the modification of the material due to the cascade. The results show that the crystal structure has a strong effect on many aspects of damage production, while other material characteristics are of lesser overall importance. In all materials studied, isolated point defects produced by the cascade are predominantly interstitials. In semiconductors, amorphous clusters are produced in the cascade core, whereas in metals most of the crystal regenerates, leaving only small vacancy-rich clusters. Large interstitial clusters found in a few events in the heavy metals were observed to form by the isolation of a high-density liquid zone during the recrystallization phase of a cascade.

731 citations

Journal ArticleDOI
TL;DR: For cascade energies of 3 and 5 keV in Cu, which are the highest energies (in reduced units) yet treated by fully dynamical simulations, it is found that local melting occurs and persists for several picoseconds.
Abstract: The role of thermal spikes in energetic displacement cascades has been investigated by molecular-dynamics computer simulation. For cascade energies of 3 and 5 keV in Cu, which are the highest energies (in reduced units) yet treated by fully dynamical simulations, it is found that local melting occurs and persists for several picoseconds. The implications of this behavior for atomic mixing, Frenkel-pair production, and point-defect clustering are discussed.

355 citations

Book ChapterDOI
TL;DR: In this article, the authors describe the fundamental mechanisms of producing atomic rearrangements and point defects in cascades, the configurations of defects in their primary state of damage, and the fates of these defects as they migrate away from their nascent locations.
Abstract: This chapter discusses displacement processes in energetic cascades. It describes the fundamental mechanisms of producing atomic rearrangements and point defects in cascades, the configurations of defects in their primary state of damage, and the fates of these defects as they migrate away from their nascent locations. When energetic particles penetrate solids, they lose their energy through a series of elastic two-body nuclear collisions with target atoms and through excitation of the electronic system. It is the elastic collisions that are of primary interest for damage creation in metals and most semiconductors because they lead to the production of Frenkel pairs, which are vacancies and self-interstitial atoms, and to rearrangements of atoms on their lattice sites. The atomic displacement process begins with the creation of a primary knock on atom (PKA), which is any target atom struck by the irradiation particle. Displacements in energetic cascades are a part of a complex dynamics that involves both energetic recoils, which are characterized by binary collisions, and intense local heating.

320 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluated the thermal stability of HenVm in Fe using the Ackland Finnis-Sinclair potential, the Wilson-Johnson potential and the Ziegler-Biersack-Littmark-Beck potential for describing the interactions of Fe-Fe, Fe-He and He-He.
Abstract: Molecular dynamics calculations were performed to evaluate the thermal stability of helium–vacancy clusters (HenVm) in Fe using the Ackland Finnis–Sinclair potential, the Wilson–Johnson potential and the Ziegler–Biersack–Littmark–Beck potential for describing the interactions of Fe–Fe, Fe–He and He–He, respectively. Both the calculated numbers of helium atoms, n, and vacancies, m, in clusters ranged from 0 to 20. The binding energies of an interstitial helium atom, an isolated vacancy and a self-interstitial iron atom to a helium–vacancy cluster were obtained from the calculated formation energies of clusters. All the binding energies do not depend much on cluster size, but they primarily depend on the helium-to-vacancy ratio (n/m) of clusters. The binding energy of a vacancy to a helium–vacancy cluster increases with the ratio, showing that helium increases cluster lifetime by dramatically reducing thermal vacancy emission. On the other hand, both the binding energies of a helium atom and an iron atom to a helium–vacancy cluster decrease with increasing the ratio, indicating that thermal emission of self-interstitial atoms (SIAs) (i.e. Frenkel-pair production), as well as thermal helium emission, may take place from the cluster of higher helium-to-vacancy ratios. The thermal stability of clusters is decided by the competitive processes among thermal emission of vacancies, SIAs and helium, depending on the helium-to-vacancy ratio of clusters. The calculated thermal stability of clusters is consistent with the experimental observations of thermal helium desorption from α-Fe during post-He-implantation annealing.

279 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of diamond-like carbon.
Abstract: Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

5,400 citations

Journal ArticleDOI
TL;DR: A review of the literature on thermal transport in nanoscale devices can be found in this article, where the authors highlight the recent developments in experiment, theory and computation that have occurred in the past ten years and summarizes the present status of the field.
Abstract: Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid–solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The promise of improved thermoelectric materials and problems of thermal management of optoelectronic devices have stimulated extensive studies of semiconductor superlattices; agreement between experiment and theory is generally poor. Advances in measurement methods, e.g., the 3ω method, time-domain thermoreflectance, sources of coherent phonons, microfabricated test structures, and the scanning thermal microscope, are enabling new capabilities for nanoscale thermal metrology.

2,933 citations

Journal ArticleDOI
TL;DR: Transparent conductors (TCs) have a multitude of applications for solar energy utilization and for energy savings, especially in buildings as discussed by the authors, which leads naturally to considerations of spectral selectivity, angular selectivity, and temporal variability of TCs, as covered in three subsequent sections.

1,471 citations

Journal ArticleDOI
TL;DR: An overview of the state of the art of ion acceleration by laser pulses as well as an outlook on its future development and perspectives are given in this article. But the main features observed in the experiments, the observed scaling with laser and plasma parameters, and the main models used both to interpret experimental data and to suggest new research directions are described.
Abstract: Ion acceleration driven by superintense laser pulses is attracting an impressive and steadily increasing effort. Motivations can be found in the applicative potential and in the perspective to investigate novel regimes as available laser intensities will be increasing. Experiments have demonstrated, over a wide range of laser and target parameters, the generation of multi-MeV proton and ion beams with unique properties such as ultrashort duration, high brilliance, and low emittance. An overview is given of the state of the art of ion acceleration by laser pulses as well as an outlook on its future development and perspectives. The main features observed in the experiments, the observed scaling with laser and plasma parameters, and the main models used both to interpret experimental data and to suggest new research directions are described.

1,221 citations

Journal ArticleDOI
TL;DR: The SRIM (formerly TRIM) Monte Carlo simulation code is widely used to compute a number of parameters relevant to ion beam implantation and ion beam processing of materials as discussed by the authors.
Abstract: The SRIM (formerly TRIM) Monte Carlo simulation code is widely used to compute a number of parameters relevant to ion beam implantation and ion beam processing of materials. It also has the capability to compute a common radiation damage exposure unit known as atomic displacements per atom (dpa). Since dpa is a standard measure of primary radiation damage production, most researchers who employ ion beams as a tool for inducing radiation damage in materials use SRIM to determine the dpa associated with their irradiations. The use of SRIM for this purpose has been evaluated and comparisons have been made with an internationally-recognized standard definition of dpa, as well as more detailed atomistic simulations of atomic displacement cascades. Differences between the standard and SRIM-based dpa are discussed and recommendations for future usage of SRIM in radiation damage studies are made. In particular, it is recommended that when direct comparisons between ion and neutron data are intended, the Kinchin–Pease option of SRIM should be selected.

1,097 citations