Tarik Ogurtani - Academia.edu (original) (raw)

Papers by Tarik Ogurtani

Research paper thumbnail of Internal friction and viscosity associated with mobile interstitials in the presence of a kink harmonically or uniformly moving in anisotropic body‐centered cubic metals

Journal of Applied Physics, Apr 15, 1984

Research paper thumbnail of Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations

Journal of Applied Physics, Aug 15, 2011

Research paper thumbnail of Motional Narrowing of Nuclear Magnetic-Resonance Lines in Manganese-Doped Lithium Fluoride

Physical Review, 1964

Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder dop... more Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder doped with manganese. Motional narrowing of the Li resonance line occurred somewhat below 400'C. Resonance absorption lines were not observable in the temperature range 200-390'C, probably because an effective loss of paramagnetic relaxation centers increased the spin-lattice relaxation time. Electron spinresonance experiments verified that the paramagnetic manganese does cluster upon heating above 200'C. A method of analysis is developed which eliminates errors due to constant linewidth contributions in the analysis of motional narrowing data in terms of diffusion activation energies. The activation energy for motion of Li ion vacancies in LiF is found to be 0.74 eV.

Research paper thumbnail of Motional Narrowing of Nuclear Magnetic-Resonance Lines in Manganese-Doped Lithium Fluoride

Physical Review, May 18, 1964

Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder dop... more Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder doped with manganese. Motional narrowing of the Li resonance line occurred somewhat below 400'C. Resonance absorption lines were not observable in the temperature range 200-390'C, probably because an effective loss of paramagnetic relaxation centers increased the spin-lattice relaxation time. Electron spinresonance experiments verified that the paramagnetic manganese does cluster upon heating above 200'C. A method of analysis is developed which eliminates errors due to constant linewidth contributions in the analysis of motional narrowing data in terms of diffusion activation energies. The activation energy for motion of Li ion vacancies in LiF is found to be 0.74 eV.

Research paper thumbnail of Effects of anisotropic surface drift diffusion on the strained heteroepitaxial nanoislands subjected to electromigration stressing

Journal of Applied Physics, Feb 21, 2022

A systematic study based on self-consistent dynamical simulations is presented for the morphologi... more A systematic study based on self-consistent dynamical simulations is presented for the morphological evolutionary behavior of an isolated thin Ge/Si nanoisland (quantum dot) on a rigid substrate exposed to electromigration forces. This morphological evolution is basically induced by the anisotropic surface drift diffusion, driven by the capillary forces, the lattice mismatch stresses, and the wetting potential. In this study, we have mainly focused on the size and shape development kinetics of quantum dots, known as the "Stranski-Krastanov" (SK) morphology, influenced by applied electromigration stresses. Emphasis is given to the effects of rotational symmetry associated with the anisotropic diffusivity in 2D space (i.e., quantum wires in 3D). The pointed bullet-shaped "Stranski-Krastanov" islands with high aspect ratios, ξ = 0.77, are formed at the cathode edge, while the whole nanoisland slightly creeps out of the initial computational domain. The favorable configuration of the Ge 20 /Si 80 alloy test module, which resulted in ζ = 0.37 enhancement in the contour surface area, has a dome shape attached to the [010] top surface of the Si substrate with a zone axis of {010}/h001i. The anisotropic surface diffusion dyadic has a fourfold rotational symmetry axis [001] lying on the (001) plane of the Si substrate, and its major axis is tilted at about f = 45°from the applied electrostatic field extended along the longitudinal axis [100] of the substrate. This particular experiment resulted in a SK singlet peak with a small satellite with a very small aspect ratio of ≅0.2 that may be appropriate for the conception of quantum optoelectronic devices or inter-band structures to generate photoelectrons having large energy spectra, thereby increasing the efficiency of photovoltaics exposed to solar radiations.

Research paper thumbnail of Influence of Paramagnetic Impurities on the Temperature Dependence of Nuclear Magnetic Resonance Lines

Physical Review, Apr 5, 1965

ABSTRACT

Research paper thumbnail of Growth Mechanism of 2D Mo 2 C on Cu via CVD

This study investigates the growth of Mo 2 C crystals via chemical vapor deposition (CVD) in the ... more This study investigates the growth of Mo 2 C crystals via chemical vapor deposition (CVD) in the presence of a carbon (H 2 /CH 4 gas)-containing environment. The study employs both theoretical and experimental approaches to investigate the vertical and lateral (in-plane) growth of Mo 2 C crystals. A physico-mathematical consideration is applied to develop an analytical forward model, which incorporates bulk diffusivities, surface diffusivities, and solubility gradients for Mo 2 C crystal growth. Coupled nonlinear flow equations have been advanced for the Mo-, Cu-, Mo 2 C layer framework and effectively predicted the Mo 2 C crystal growth rate for both vertical and lateral directions. Forming the Mo 2 C crystal height and diameter was directly correlated with copper layer thickness and time using the forward model and then validated by the experiments together with SEM and AFM studies. Studies showed that the Cu layer thickness plays a crucial role in controlling the height of the Mo 2 C crystal while it is not that critical in changing the lateral dimension of the crystal. Beyond simply enhancing Mo 2 C crystal growth and property-processing relationship, this study demonstrated the synthesis of designer Mo 2 C, which can be tailored to the needs of specific applications. This forward model will enable us to further enhance and exploit the family of analogs of materials previously demonstrated by other methods.

Research paper thumbnail of Irreversible thermodynamics of surfaces and interfaces: Special reference to the strained thin solid films on the substrates: Theory and practice

Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillar... more Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations

Research paper thumbnail of Anomalous Amplitude Dependence Dislocation Damping

Research paper thumbnail of Effects of anisotropic surface drift diffusion on the strained heteroepitaxial nanoislands subjected to electromigration stressing

Journal of Applied Physics, 2022

A systematic study based on self-consistent dynamical simulations is presented for the morphologi... more A systematic study based on self-consistent dynamical simulations is presented for the morphological evolutionary behavior of an isolated thin Ge/Si nanoisland (quantum dot) on a rigid substrate exposed to electromigration forces. This morphological evolution is basically induced by the anisotropic surface drift diffusion, driven by the capillary forces, the lattice mismatch stresses, and the wetting potential. In this study, we have mainly focused on the size and shape development kinetics of quantum dots, known as the "Stranski-Krastanov" (SK) morphology, influenced by applied electromigration stresses. Emphasis is given to the effects of rotational symmetry associated with the anisotropic diffusivity in 2D space (i.e., quantum wires in 3D). The pointed bullet-shaped "Stranski-Krastanov" islands with high aspect ratios, ξ = 0.77, are formed at the cathode edge, while the whole nanoisland slightly creeps out of the initial computational domain. The favorable configuration of the Ge 20 /Si 80 alloy test module, which resulted in ζ = 0.37 enhancement in the contour surface area, has a dome shape attached to the [010] top surface of the Si substrate with a zone axis of {010}/h001i. The anisotropic surface diffusion dyadic has a fourfold rotational symmetry axis [001] lying on the (001) plane of the Si substrate, and its major axis is tilted at about f = 45°from the applied electrostatic field extended along the longitudinal axis [100] of the substrate. This particular experiment resulted in a SK singlet peak with a small satellite with a very small aspect ratio of ≅0.2 that may be appropriate for the conception of quantum optoelectronic devices or inter-band structures to generate photoelectrons having large energy spectra, thereby increasing the efficiency of photovoltaics exposed to solar radiations.

Research paper thumbnail of Stranski-Krastanow islanding initiated on the stochastic rough surfaces of the epitaxially strained thin films

Journal of Applied Physics, 2014

ABSTRACT Quantum dots (QD) have discrete energy spectrum, which can be adjusted over a wide range... more ABSTRACT Quantum dots (QD) have discrete energy spectrum, which can be adjusted over a wide range by tuning composition, density, size, lattice strain, and morphology. These features make quantum dots attractive for the design and fabrication of novel electronic, magnetic and photonic devices and other functional materials used in cutting-edge applications. The formation of QD on epitaxially strained thin film surfaces, known as Stranski-Krastanow (SK) islands, has attracted great attention due to their unique electronic properties. Here, we present a systematic dynamical simulation study for the spontaneous evolution of the SK islands on the stochastically rough surfaces (nucleationless growth). During the development of SK islands through the mass accumulation at randomly selected regions of the film via surface drift-diffusion (induced by the capillary and mismatch stresses) with and/or without growth, one also observes the formation of an extremely thin wetting layer having a thickness of a few Angstroms. Above a certain threshold level of the mismatch strain and/or the size of the patch, the formation of multiple islands separated by shallow wetting layers is also observed as metastable states such as doublets even multiplets. These islands are converted into a distinct SK islands after long annealing times by coalescence through the long range surface diffusion. Extensive computer simulation studies demonstrated that after an initial transient regime, there is a strong quadratic relationship between the height of the SK singlet and the intensity of the lattice mismatch strain (in a wide range of stresses up to 8.5GPa for germanium thin crystalline films), with the exception at those critical points where the morphological (shape change with necking) transition takes place.VC 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4883295]

Research paper thumbnail of Diffusion of Nitrogen in Niobium, with Special Reference to Temperature Dependence of the Activation Energy

Transactions of the Japan Institute of Metals

The hardness profile was correlated with the concentration of nitrogen in niobium. It was found t... more The hardness profile was correlated with the concentration of nitrogen in niobium. It was found that the diffusion kinetics in this temperature range could be represented by a single Arrhenius type rate equation. The activation energy and the pre-exponential factor were found to be 24.9kcal/mol and 0.0023cm2/sec, respectively. The analysis of available experimental data for diffusion of nitrogen in niobium shows that the apparent activation energy decreases with increasing temperature.. An explanation can be formulated in terms of a temperature dependence of the motion enthalpy Hm of interstitial nitrogen atoms. Hm is found to decrease from 38.6kcal/mol to 24.7kcal/mol between

Research paper thumbnail of Thermal Grooving by Surface Diffusion: a Review of Classical Thermo-Kinetics Approach

Hittite Journal of Science and Engineering

P olycrystalline materials are composed of tiny perfect crystalline regions (grains) in between i... more P olycrystalline materials are composed of tiny perfect crystalline regions (grains) in between internal interfaces called grain boundaries. Grain boundaries and the external interfaces (i.e. free surfaces which separate the material from the environment) determine the morphology of the material at a major extent. A material may change its morphology through interface motion if a driving force exists. An important special case, which is the focus of this review, is the grain boundary grooving. Wherever a grain boundary intersects a free surface and whenever the topographic variation associated with the atomic motion is favored by total free energy dissipation, the surface grooves. Grooving can occur via several mass transport mechanisms, such as surface diffusion, bulk diffusion, and evaporation and condensation. Surface diffusion dominates for temperatures far below the melting temperature, and for grooves less than 10 micron in size [1]. If the surface evolution is driven solely by the total excess free energies associated with the interfaces the resulting force for motion is conventionally called a capillary force,

Research paper thumbnail of The effects of acid pretreatment and surface stresses on the evolution of impurity clusters and graphene formation on Cu foil

Research paper thumbnail of Nonlinear Theory of the Power Dissipation Due to the Motion of Heavy Intersitials in Oscillating Inhomogeneous Fields with Strong Static Bias

Le Journal de Physique Colloques, 1987

Research paper thumbnail of A computer simulation of void dynamics under the action of electromigration and capillary forces

Research paper thumbnail of Hillock formation by surface drift-diffusion driven by the gradient of elastic dipole interaction energy under compressive stresses in bi-crystalline thin films

Hittite Journal of Science and Engineering, 2015

G rain boundary (GB) thermal grooving is a capillary driven surface morphological evolution, and ... more G rain boundary (GB) thermal grooving is a capillary driven surface morphological evolution, and observed in the vicinity of the grain boundary-free surface junctions in polycrystalline materials at rather elevated temperatures. When the underlying bulk system is exposed to the external and/or internal stress fields the problem becomes much more complicated. One of the most widely employed method to study the effects force fields on the GB grooving, is to couple the capillary-driven surface diffusion with the steady state atomic flux induced by the normal component of the surface

Research paper thumbnail of Computer Simulation of voids 2001

A comprehensive picture of void dynamics in connection with the critical morphological evolution ... more A comprehensive picture of void dynamics in connection with the critical morphological evolution has been developed in order to understand the conditions under which premature failure of metallic thin interconnects occurs. Our mathematical model on the mass flow and accumulation on void surfaces, under the action of applied electrostatic and elastostatic force fields, and capillary effects, follows an irreversible but discrete thermodynamic formulation of interphases and surfaces. This formalism also takes into account in a natural way the mass transfer process ͑the void growth͒, between bulk phase and the void region in multi-component systems, in terms of the normalized local values of Gibbs free energy of transformation with respect to the specific surface Gibbs free energy, in addition to the contribution due to local curvature of the advancing reaction front, rather rigorously.

Research paper thumbnail of Influence of Paramagnetic Impurities on the Temperature Dependence of Nuclear Magnetic Resonance Lines

Physical Review, 1965

ABSTRACT

Research paper thumbnail of The Theory of Strain Amplitude Dependent Dislocation Damping in the Presence of Uniform Point Defect Dragging

Le Journal de Physique Colloques, 1983

The strain-amplitude and frequency-dependent internal friction due to movements of dislocations i... more The strain-amplitude and frequency-dependent internal friction due to movements of dislocations in the presence of uniform point defect draggiv,~ and randomly distributed, weak pinning obstacles is investigated using the string model. By making use of computer simulations with the catastrophic breakaway distribution function and uniform point defect dragging, the internal friction coefficient is obtained as a function of the stress amplitude, homologous temperature, driving frequency, and densities of the dragging point defects and the weak pinning obstacles.

Research paper thumbnail of Internal friction and viscosity associated with mobile interstitials in the presence of a kink harmonically or uniformly moving in anisotropic body‐centered cubic metals

Journal of Applied Physics, Apr 15, 1984

Research paper thumbnail of Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations

Journal of Applied Physics, Aug 15, 2011

Research paper thumbnail of Motional Narrowing of Nuclear Magnetic-Resonance Lines in Manganese-Doped Lithium Fluoride

Physical Review, 1964

Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder dop... more Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder doped with manganese. Motional narrowing of the Li resonance line occurred somewhat below 400'C. Resonance absorption lines were not observable in the temperature range 200-390'C, probably because an effective loss of paramagnetic relaxation centers increased the spin-lattice relaxation time. Electron spinresonance experiments verified that the paramagnetic manganese does cluster upon heating above 200'C. A method of analysis is developed which eliminates errors due to constant linewidth contributions in the analysis of motional narrowing data in terms of diffusion activation energies. The activation energy for motion of Li ion vacancies in LiF is found to be 0.74 eV.

Research paper thumbnail of Motional Narrowing of Nuclear Magnetic-Resonance Lines in Manganese-Doped Lithium Fluoride

Physical Review, May 18, 1964

Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder dop... more Nuclear magnetic-resonance experiments have been performed between 25 and 550'C in LiF powder doped with manganese. Motional narrowing of the Li resonance line occurred somewhat below 400'C. Resonance absorption lines were not observable in the temperature range 200-390'C, probably because an effective loss of paramagnetic relaxation centers increased the spin-lattice relaxation time. Electron spinresonance experiments verified that the paramagnetic manganese does cluster upon heating above 200'C. A method of analysis is developed which eliminates errors due to constant linewidth contributions in the analysis of motional narrowing data in terms of diffusion activation energies. The activation energy for motion of Li ion vacancies in LiF is found to be 0.74 eV.

Research paper thumbnail of Effects of anisotropic surface drift diffusion on the strained heteroepitaxial nanoislands subjected to electromigration stressing

Journal of Applied Physics, Feb 21, 2022

A systematic study based on self-consistent dynamical simulations is presented for the morphologi... more A systematic study based on self-consistent dynamical simulations is presented for the morphological evolutionary behavior of an isolated thin Ge/Si nanoisland (quantum dot) on a rigid substrate exposed to electromigration forces. This morphological evolution is basically induced by the anisotropic surface drift diffusion, driven by the capillary forces, the lattice mismatch stresses, and the wetting potential. In this study, we have mainly focused on the size and shape development kinetics of quantum dots, known as the "Stranski-Krastanov" (SK) morphology, influenced by applied electromigration stresses. Emphasis is given to the effects of rotational symmetry associated with the anisotropic diffusivity in 2D space (i.e., quantum wires in 3D). The pointed bullet-shaped "Stranski-Krastanov" islands with high aspect ratios, ξ = 0.77, are formed at the cathode edge, while the whole nanoisland slightly creeps out of the initial computational domain. The favorable configuration of the Ge 20 /Si 80 alloy test module, which resulted in ζ = 0.37 enhancement in the contour surface area, has a dome shape attached to the [010] top surface of the Si substrate with a zone axis of {010}/h001i. The anisotropic surface diffusion dyadic has a fourfold rotational symmetry axis [001] lying on the (001) plane of the Si substrate, and its major axis is tilted at about f = 45°from the applied electrostatic field extended along the longitudinal axis [100] of the substrate. This particular experiment resulted in a SK singlet peak with a small satellite with a very small aspect ratio of ≅0.2 that may be appropriate for the conception of quantum optoelectronic devices or inter-band structures to generate photoelectrons having large energy spectra, thereby increasing the efficiency of photovoltaics exposed to solar radiations.

Research paper thumbnail of Influence of Paramagnetic Impurities on the Temperature Dependence of Nuclear Magnetic Resonance Lines

Physical Review, Apr 5, 1965

ABSTRACT

Research paper thumbnail of Growth Mechanism of 2D Mo 2 C on Cu via CVD

This study investigates the growth of Mo 2 C crystals via chemical vapor deposition (CVD) in the ... more This study investigates the growth of Mo 2 C crystals via chemical vapor deposition (CVD) in the presence of a carbon (H 2 /CH 4 gas)-containing environment. The study employs both theoretical and experimental approaches to investigate the vertical and lateral (in-plane) growth of Mo 2 C crystals. A physico-mathematical consideration is applied to develop an analytical forward model, which incorporates bulk diffusivities, surface diffusivities, and solubility gradients for Mo 2 C crystal growth. Coupled nonlinear flow equations have been advanced for the Mo-, Cu-, Mo 2 C layer framework and effectively predicted the Mo 2 C crystal growth rate for both vertical and lateral directions. Forming the Mo 2 C crystal height and diameter was directly correlated with copper layer thickness and time using the forward model and then validated by the experiments together with SEM and AFM studies. Studies showed that the Cu layer thickness plays a crucial role in controlling the height of the Mo 2 C crystal while it is not that critical in changing the lateral dimension of the crystal. Beyond simply enhancing Mo 2 C crystal growth and property-processing relationship, this study demonstrated the synthesis of designer Mo 2 C, which can be tailored to the needs of specific applications. This forward model will enable us to further enhance and exploit the family of analogs of materials previously demonstrated by other methods.

Research paper thumbnail of Irreversible thermodynamics of surfaces and interfaces: Special reference to the strained thin solid films on the substrates: Theory and practice

Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillar... more Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations

Research paper thumbnail of Anomalous Amplitude Dependence Dislocation Damping

Research paper thumbnail of Effects of anisotropic surface drift diffusion on the strained heteroepitaxial nanoislands subjected to electromigration stressing

Journal of Applied Physics, 2022

A systematic study based on self-consistent dynamical simulations is presented for the morphologi... more A systematic study based on self-consistent dynamical simulations is presented for the morphological evolutionary behavior of an isolated thin Ge/Si nanoisland (quantum dot) on a rigid substrate exposed to electromigration forces. This morphological evolution is basically induced by the anisotropic surface drift diffusion, driven by the capillary forces, the lattice mismatch stresses, and the wetting potential. In this study, we have mainly focused on the size and shape development kinetics of quantum dots, known as the "Stranski-Krastanov" (SK) morphology, influenced by applied electromigration stresses. Emphasis is given to the effects of rotational symmetry associated with the anisotropic diffusivity in 2D space (i.e., quantum wires in 3D). The pointed bullet-shaped "Stranski-Krastanov" islands with high aspect ratios, ξ = 0.77, are formed at the cathode edge, while the whole nanoisland slightly creeps out of the initial computational domain. The favorable configuration of the Ge 20 /Si 80 alloy test module, which resulted in ζ = 0.37 enhancement in the contour surface area, has a dome shape attached to the [010] top surface of the Si substrate with a zone axis of {010}/h001i. The anisotropic surface diffusion dyadic has a fourfold rotational symmetry axis [001] lying on the (001) plane of the Si substrate, and its major axis is tilted at about f = 45°from the applied electrostatic field extended along the longitudinal axis [100] of the substrate. This particular experiment resulted in a SK singlet peak with a small satellite with a very small aspect ratio of ≅0.2 that may be appropriate for the conception of quantum optoelectronic devices or inter-band structures to generate photoelectrons having large energy spectra, thereby increasing the efficiency of photovoltaics exposed to solar radiations.

Research paper thumbnail of Stranski-Krastanow islanding initiated on the stochastic rough surfaces of the epitaxially strained thin films

Journal of Applied Physics, 2014

ABSTRACT Quantum dots (QD) have discrete energy spectrum, which can be adjusted over a wide range... more ABSTRACT Quantum dots (QD) have discrete energy spectrum, which can be adjusted over a wide range by tuning composition, density, size, lattice strain, and morphology. These features make quantum dots attractive for the design and fabrication of novel electronic, magnetic and photonic devices and other functional materials used in cutting-edge applications. The formation of QD on epitaxially strained thin film surfaces, known as Stranski-Krastanow (SK) islands, has attracted great attention due to their unique electronic properties. Here, we present a systematic dynamical simulation study for the spontaneous evolution of the SK islands on the stochastically rough surfaces (nucleationless growth). During the development of SK islands through the mass accumulation at randomly selected regions of the film via surface drift-diffusion (induced by the capillary and mismatch stresses) with and/or without growth, one also observes the formation of an extremely thin wetting layer having a thickness of a few Angstroms. Above a certain threshold level of the mismatch strain and/or the size of the patch, the formation of multiple islands separated by shallow wetting layers is also observed as metastable states such as doublets even multiplets. These islands are converted into a distinct SK islands after long annealing times by coalescence through the long range surface diffusion. Extensive computer simulation studies demonstrated that after an initial transient regime, there is a strong quadratic relationship between the height of the SK singlet and the intensity of the lattice mismatch strain (in a wide range of stresses up to 8.5GPa for germanium thin crystalline films), with the exception at those critical points where the morphological (shape change with necking) transition takes place.VC 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4883295]

Research paper thumbnail of Diffusion of Nitrogen in Niobium, with Special Reference to Temperature Dependence of the Activation Energy

Transactions of the Japan Institute of Metals

The hardness profile was correlated with the concentration of nitrogen in niobium. It was found t... more The hardness profile was correlated with the concentration of nitrogen in niobium. It was found that the diffusion kinetics in this temperature range could be represented by a single Arrhenius type rate equation. The activation energy and the pre-exponential factor were found to be 24.9kcal/mol and 0.0023cm2/sec, respectively. The analysis of available experimental data for diffusion of nitrogen in niobium shows that the apparent activation energy decreases with increasing temperature.. An explanation can be formulated in terms of a temperature dependence of the motion enthalpy Hm of interstitial nitrogen atoms. Hm is found to decrease from 38.6kcal/mol to 24.7kcal/mol between

Research paper thumbnail of Thermal Grooving by Surface Diffusion: a Review of Classical Thermo-Kinetics Approach

Hittite Journal of Science and Engineering

P olycrystalline materials are composed of tiny perfect crystalline regions (grains) in between i... more P olycrystalline materials are composed of tiny perfect crystalline regions (grains) in between internal interfaces called grain boundaries. Grain boundaries and the external interfaces (i.e. free surfaces which separate the material from the environment) determine the morphology of the material at a major extent. A material may change its morphology through interface motion if a driving force exists. An important special case, which is the focus of this review, is the grain boundary grooving. Wherever a grain boundary intersects a free surface and whenever the topographic variation associated with the atomic motion is favored by total free energy dissipation, the surface grooves. Grooving can occur via several mass transport mechanisms, such as surface diffusion, bulk diffusion, and evaporation and condensation. Surface diffusion dominates for temperatures far below the melting temperature, and for grooves less than 10 micron in size [1]. If the surface evolution is driven solely by the total excess free energies associated with the interfaces the resulting force for motion is conventionally called a capillary force,

Research paper thumbnail of The effects of acid pretreatment and surface stresses on the evolution of impurity clusters and graphene formation on Cu foil

Research paper thumbnail of Nonlinear Theory of the Power Dissipation Due to the Motion of Heavy Intersitials in Oscillating Inhomogeneous Fields with Strong Static Bias

Le Journal de Physique Colloques, 1987

Research paper thumbnail of A computer simulation of void dynamics under the action of electromigration and capillary forces

Research paper thumbnail of Hillock formation by surface drift-diffusion driven by the gradient of elastic dipole interaction energy under compressive stresses in bi-crystalline thin films

Hittite Journal of Science and Engineering, 2015

G rain boundary (GB) thermal grooving is a capillary driven surface morphological evolution, and ... more G rain boundary (GB) thermal grooving is a capillary driven surface morphological evolution, and observed in the vicinity of the grain boundary-free surface junctions in polycrystalline materials at rather elevated temperatures. When the underlying bulk system is exposed to the external and/or internal stress fields the problem becomes much more complicated. One of the most widely employed method to study the effects force fields on the GB grooving, is to couple the capillary-driven surface diffusion with the steady state atomic flux induced by the normal component of the surface

Research paper thumbnail of Computer Simulation of voids 2001

A comprehensive picture of void dynamics in connection with the critical morphological evolution ... more A comprehensive picture of void dynamics in connection with the critical morphological evolution has been developed in order to understand the conditions under which premature failure of metallic thin interconnects occurs. Our mathematical model on the mass flow and accumulation on void surfaces, under the action of applied electrostatic and elastostatic force fields, and capillary effects, follows an irreversible but discrete thermodynamic formulation of interphases and surfaces. This formalism also takes into account in a natural way the mass transfer process ͑the void growth͒, between bulk phase and the void region in multi-component systems, in terms of the normalized local values of Gibbs free energy of transformation with respect to the specific surface Gibbs free energy, in addition to the contribution due to local curvature of the advancing reaction front, rather rigorously.

Research paper thumbnail of Influence of Paramagnetic Impurities on the Temperature Dependence of Nuclear Magnetic Resonance Lines

Physical Review, 1965

ABSTRACT

Research paper thumbnail of The Theory of Strain Amplitude Dependent Dislocation Damping in the Presence of Uniform Point Defect Dragging

Le Journal de Physique Colloques, 1983

The strain-amplitude and frequency-dependent internal friction due to movements of dislocations i... more The strain-amplitude and frequency-dependent internal friction due to movements of dislocations in the presence of uniform point defect draggiv,~ and randomly distributed, weak pinning obstacles is investigated using the string model. By making use of computer simulations with the catastrophic breakaway distribution function and uniform point defect dragging, the internal friction coefficient is obtained as a function of the stress amplitude, homologous temperature, driving frequency, and densities of the dragging point defects and the weak pinning obstacles.