Publications

The deleterious low-temperature tetragonal phases in prototypical Pt-based superalloys have variously been reported as taking the tI16-U₃Si (DOc), tI16-Ir₃Si (DOc′) and tP16-Pt₃Ga structure-types in contrast to the high-temperature cubic cP4-Cu₃Au (L12) phase. We have investigated the relative...

Density functional theory (DFT) is used to reveal that the polycrystalline Young’s modulus ͑ E of graphite triples as it is lithiated to LiC₆. This behavior is captured in a linear relationship between E and lithium concentration suitable for continuum-scale models aimed at predicting...

The temperature-dependent diffusion coefficients of interstitial hydrogen, deuterium, and tritium in nickel are computed using transition state theory. The coefficient of thermal expansion, the enthalpy and entropy of activation, and the pre-exponential factor of the diffusion coefficient are...

During the past decade, computer simulations based on a quantum-mechanical description of the interactions between electrons and between electrons and atomic nuclei have developed an increasingly important impact on solid-state physics and chemistry and on materials science—promoting not only a...

Skutterudite based materials are important for thermoelectric applications. In order to be able to tune the thermoelectric properties, it is necessary to understand the mechanism of thermal conductivity, which, in turn, is strongly influenced by the lattice dynamics. The lattice dynamics of the...

The structural, electronic, and phonon properties of the cubic and tetragonal phase of SrTiO₃ and BaTiO₃ are studied from ab initio. The calculations are performed in the projector augmented wave density-functional theory framework using the local density approximation, gradient corrected...

We present a detailed study of the adsorption of CO on Cu, Rh, and Pt (111) surfaces in top and hollow sites. The study has been performed using the local density approximation, the gradient corrected functional PBE, and the hybrid Hartree-Fock density functionals PBE0 and HSE03 within the...

Combining experiments and ab initio models we report on SrPt₄Ge₁₂ and BaPt₄Ge₁₂ as members of a novel class of superconducting skutterudites, where Sr or Ba atoms stabilize a framework entirely formed by Ge atoms. Below Tc=5.35 and 5.10 K forBaPt₄Ge₁₂ and SrPt₄Ge₁₂, respectively, electron-phonon...

Self-consistent GW calculations, maintaining only the quasiparticle part of the Green's function G, are reported for a wide class of materials, including small gap semiconductors and large gap insulators. We show that the inclusion of the attractive electron-hole interaction via an effective...

First-principles modeling, experimental, and thermodynamic methodologies were integrated to facilitate a fundamentally guided investigation of quaternary complex hydride compounds within the bialkali Na−Li−Al−H hydrogen storage system. The integrated approach has broad utility for the discovery...

By an ab initio density functional approach, structural, magnetic, vibrational, and thermodynamic properties of HfMn₂ were studied. These properties were derived for the C14, C15, and C36 crystal structures, revealing a close energetical competition between the ferromagnetically ordered phases...

In this work we derive closed expressions for the head of the frequency-dependent microscopic polarizability matrix in the projector-augmented wave (PAW) methodology. Contrary to previous applications, the lon- gitudinal expression is utilized, resulting in dielectric properties that are...

Present local and semilocal functionals show significant errors, for instance, in the energetics of small molecules and in the description of band gaps. One possible solution to these problems is the introduction of exact exchange and hybrid functionals. A plane-wave-based algorithm was...

A density functional theory investigation of the recently identified hydrogen storage reaction LiNH₂ + LiH ↔ Li₂NH + H₂ is described. The electronic structure and enthalpy of formation ΔH of each constituent are calculated in both the generalized gradient approximation (GGA) and the local density...

The simulation of vibrational properties and finite temperature effects based on ab initio calculation of phonons within the direct approach is discussed.

Using a first-principles methodology, we investigated the effect of diamond surface termination on the work of separation ( W sep) , interface geometry, bond character, and adhesive transfer of three Al/diamond interfaces, viz., Al(111)/C(111)-1×1, Al(111)/C(111)-2×1 and Al(111)/C(111)-1×1:H....

Ab initio calculations of the basic properties of solids have advanced significantly, and it is now possible to simply access a crystal structure database, and from the given constituent atoms and their positions, calculate reasonably accurate values for elastic constants and thermomechanical...

The crystallographic structure of switchable mirror material YD₃ is still under debate. Aiming at a final structure assessment, currently considered structure models of P-3c1 , P63cm and P63 symmetry are studied by means of ab initio methods. The relative stability of these candidate structures...

Accurate band structures of binary semiconductors AB (A = Al, Ga, In and B = P, As, Sb) and selected ternary III–V semiconductors were calculated using an all-electron screened exchange approach within the full potential linearized augmented plane-wave method. Fundamental band gaps and Γ–L and Γ...

Grand canonical ensemble Monte Carlo simulations of the adsorption properties of several model faujasite zeolites were performed using the statistical bias method. The results enable a better understanding of the effect of cation exchange in the selective adsorption of binary mixtures of para-...

Quasiparticle electronic band structures for ternary InGaAs and InGaSb systems, modeled by a luzonite structure, have been obtained using the screened-exchange local-density approximation approach. We focus our attention on energy transitions relevant for the electron-hole pair lifetime and, in...

We have employed Monte Carlo simulation in the NPT ensemble to determine the molar volume and the compressibility factor of naturally occurring hydrocarbon gas mixtures. The simulation results were compared to experimental data as well as to predictions based on both the Peng–Robinson and AGA 8...