Related papers: Oxygen impurities in NiAl: Relaxation effects
We theoretically study the atomic structure and energetics of silicon and silicon-nitrogen impurities in graphene. Using density-functional theory, we get insight into the atomic structures of the impurities, evaluate their formation…
In this work we undertake the problem of a transition metal impurity in an oxide. We present an ab-initio study of the relaxations introduced in TiO2 when a Cd impurity replaces substitutionally a Ti atom. Using the Full-Potential…
We use thermodynamic and neutron scattering measurements to study the effect of oxygen annealing on the superconductivity and magnetism in Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-\delta}$. Although the transition temperature $T_c$ measured by…
While ultra-thin layers of the LaNiO$_3$ film exhibit a remarkable metal-insulator transition as the film thickness becomes smaller than a few unit cell (u.c.), the formation of oxygen vacancies and their effects on the correlated…
The electronic structure and magnetism in the sodium nickelate NaNiO_2 in the low-temperature phase is studied from density-functional calculations using the linear muffin-tin orbitals method. An antiferromagnetic solution with a magnetic…
While defects such as oxygen vacancies in correlated materials can modify their electronic properties dramatically, understanding the microscopic origin of electronic correlations in materials with defects has been elusive. Lanthanum…
We employ density-functional-theory calculations to analyze the interactions between oxygen interstitial atoms and <a>-type screw dislocations (<a> = a<11-20>/3 ) in alpha-titanium, based on investigations of generalized stacking fault…
Many nanoelectronic devices rely on thin dielectric barriers through which electrons tunnel. For instance, aluminium oxide barriers are used as Josephson junctions in superconducting electronics. The reproducibility and drift of circuit…
Oxygen vacancy is intrinsically coupled with magnetic, electronic and transport properties of transition-metal oxide materials and directly determines their multifunctionality. Here, we demonstrate reversible control of oxygen content by…
The occupation of d-orbitals controls the magnitude and anisotropy of the inter-atomic electron transfer in transition metal oxides and hence exerts a key influence on their chemical bonding and physical properties. Atomic-scale modulations…
Atom probe tomography (APT), electron probe microanalysis (EPMA) and nanoindentation were used to characterise the oxygen-rich layer on an in-service jet engine compressor disc, manufactured from the titanium alloy TIMETAL 834. Oxygen…
Static and dynamic changes induced by adsorption of atomic hydrogen on the NiAl(110) lattice at 130 K have been examined as a function of adsorbate coverage. Adsorbed hydrogen exists in three distinct phases. At low coverages the hydrogen…
We demonstrate a thermodynamic formulation to quantify defect formation energetics in an insulator under high electric field. As a model system, we analyzed neutral oxygen vacancies (color centers) in alkaline-earth-metal binary oxides…
A thermodynamic model based on the law of mass action is used to calculate concentrations of elementary point defects and to determine site preferences of solute atoms in ordered alloys. Combinations of lattice vacancies, antisite atoms and…
We investigate the effects of impurity scattering on the conductance of metallic carbon nanotubes as a function of the relative separation of the impurities. First we compute the conductance of a clean (6,6) tube, and the effect of model…
Using Tyablikov's decoupling approximation, we calculate the initial suppression rate of the Neel temperature, $R_{IS}=-lim_{x-> 0} T^{-1}_{N} dT_{N}/dx$, in a quasi two-dimensional diluted Heisenberg antiferromagnet with nonmagnetic…
We present systematic investigations on the shock responses of nanoporous aluminum (np-Al) by nonequilibrium molecular dynamics simulations. The dislocation nucleation sites are found to concentrate in low latitude region near the equator…
Plasticity in zirconium alloys is mainly controlled by the interaction of 1/3 1210 screw dislocations with oxygen atoms in interstitial octahedral sites of the hexagonal close-packed lattice. This process is studied here using ab initio…
Ni/Al reactive multilayers are promising materials for applications requiring controlled local energy release and superior mechanical performance. This study systematically investigates the impact of compositional variations, ranging from…
The composition and site occupancy of Mg within ordered {\delta} precipitates in a model Al Mg Li alloy have been characterized by atom probe microscopy and first-principles simulations. The concentration in the precipitates is found to be…