We present a theoretical study of the interaction of vacancies with a tilt grain boundary in aluminum based on the density functional theory. The grain boundary volume expansion and vacancy induced contraction are calculated and compared for the nearest-neighbor atoms, and the former is found to be smaller than the latter. The formation energy of a vacancy placed at various layers in the grain ...

In the wake of the housing market crash in the United States in the late 2000s, images of abandoned homes on the urban periphery of American cities dominated international media coverage. This narrative of peri-urban over-extension was used by media documenting the housing crisis in Mexico, despite the profound differences in context, namely the role of the government in housing finance. This p...

-The nanostructure transformation associated with electro-optical properties via post-annealing of indium tin oxide film (ITO) is investigated by increasing post-annealing temperature in ambient oxygen. Although oxygen vacancy and activation Sn ions contribute to conductivity of ITO film, the oxygen vacancy inevitably reduces during posting annealing, but Sn-O related bonds are oppositely incre...

At a vacant lattice cell positron-ion repulsion is reduced leading to positron trapping. This causes observable changes in annihilation characteristics: the positron lifetime increases and the positron-electron momentum distribution narrows. Positron trapping in semiconductors is analogous to carrier capture. Due to the long-range Coulomb interaction, the charge state of a vacancy has a strong ...

Formation of metal rich conductive filaments and their rearrangements determine the switching characteristics in HfO2 based resistive random access memory (RRAM) devices. The initiation of a filament formation process may occur either via aggregation of pre-existing vacancies randomly distributed in the oxide or via generation of new oxygen vacancies close to the pre-existing ones. We evaluate ...

Vacancy chains can be tracked in any context where a scarce resource flows through different owners, such as employment positions. However, under certain conditions vacancy chains, rather than market or other forms of competition, determine the allocation of the resource. This article develops a computational and formal model of vacancy chains as a mechanism for resource allocation in order to ...

We have performed density-functional pseudopotential calculations to investigate the electronic structure, atomic configurations, and formation energies of native point defects and impurities in AlN. For the native defects, the nitrogen vacancy has the lowest formation energy in p-type material and the aluminum vacancy has the lowest formation energy in n-type material. Under n-type conditions ...

Cuprous oxide (Cu2O) is an attractive material for solar energy applications, but its photoconductivity is limited by minority carrier recombination caused by native defect trap states. We examine the creation of trap states by cation vacancies, using first principles calculations based on density functional theory (DFT) to analyze the electronic structure and calculate formation energies. With...

We develop a mesoscopic dislocation dynamics model for vacancy-assisted dislocation climb by upscalings from a stochastic model on the atomistic scale. Our models incorporate microscopic mechanisms of (i) bulk diffusion of vacancies, (ii) vacancy exchange dynamics between bulk and dislocation core, (iii) vacancy pipe diffusion along the dislocation core, and (iv) vacancy attachment-detachment k...

Perturbed angular correlation of gamma rays (PAC) was applied to measure concentrations of point defects in quenched and milled intermetallic compounds. Two systems with high ordering energies were studied, PdIn and NiAl, with principal results obtained for PdIn. The defects, lattice vacancies and antisite atoms, were detected by quadrupole interactions induced at nuclei of nearby In/Cd probe a...