Native defects in cuprous oxide Cu2O are investigated by using first-principles calculations based on density-functional theory. Considering the formation of copper and oxygen vacancies, antisites and interstitials, and a copper split-vacancy complex defect, we analyze the electronic structure and calculate their respective formation energies as a function of the change in Fermi level under bot...

Engineering single atomic defects into wide bandgap materials has become an attractive field in recent years due to emerging applications such as solid-state quantum bits and sensors. The simplest atomic-scale defect is the lattice vacancy which often a constituent part of more complex nitrogen-vacancy (NV) centre diamond, therefore understanding formation mechanisms precision engineering vacan...

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 ...

In this article, we examine the Young modulus of (6, m) boron-nitride nanotubes with vacancy and functionalization defects. We employ molecular dynamics simulations using the Parrinello-Rahman approach. To this end, all systems are modeled with a reactive many-body bond order Tersoff-potential with parameters due to Matsunaga et al [1], which is able to accurately describe covalent bonding. We ...

This article reports stable photoluminescence and high-contrast optically detected electron spin resonance (ODESR) from single nitrogen-vacancy (NV) defect centers created within ultrasmall, disperse nanodiamonds of radius less than 4 nm. Unexpectedly, the efficiency for the production of NV fluorescent defects by electron irradiation is found to be independent of the size of the nanocrystals. ...

We investigate the effect of cell-size on the energetics of vacancies in Aluminum using orbital-free density functional theory with non-local kinetic energy functionals. Extending the recently developed coarse-graining techniques based on quasi-continuum reduction to include non-local kinetic energy functionals, we consider cell-sizes up to a million atoms in this study. We find remarkable cell...

Motivated by recent developments in solid electrolytes based on lithium phosphorous oxynitride (LiPON) materials, we carried out computer simulations in order to develop an understanding of the detailed mechanisms of ionic transport. Starting with crystalline Li3PO4, we investigated some possible structures of isolated defects associated with extrinsic Li ion vacancies and interstitials. In par...

In this contribution, the production of defects in radiation fields and their evolution toward equilibrium in silicon for detector uses has been modelled. In the quantitative model developed, the generation rate of primary defects is calculated starting from the projectile silicon interaction and from recoil energy redistribution in the lattice. Vacancy-interstitial annihilation, interstitial m...

The native point defects in Fe2O3 are theoretically investigated using ab initio methods based on the GGA + U formalism. We consider vacancies and interstitials of Fe and O atoms as well as the electron polaron as Fe(II) defects at the host Fe(III) site. The formation energies and charge transition levels are computed for each defect type with careful elimination of size effects of the supercel...

Vacancies represent an important class of crystallographic defects, and their behaviors can be strongly coupled with relevant material properties. In this work, we study the dynamics of generic n-point vacancies in two-dimensional Lennard-Jones crystals in several thermodynamic states. Simulations reveal the spectrum of distinct, size-dependent vacancy dynamics, including the nonmonotonously va...