Effects of disorder in metallic systems from First-Principles calculations / Christian Asker.

• In this thesis, quantum-mechanical calculations within density-functional theory on metallic systems are presented. The overarching goal has been to investigate effects of disorder. In particular, one of the properties investigated is the bindingenergy shifts for core electrons in binary alloys using different theoretical methods. These methods are compared with each other and with experimental results. One such method, the so-called Slater-Janak transition state method relies on the assumption that the single-particle eigenvalues within density-functional theory are linear functions of their respective occupation number. This assumption is investigated and it is found that while the eigenvalues to a first approximation show linear behavior, there are also nonlinearities which can influence the core-level binding energy shifts. Another area of investigation has been iron based alloys at pressures corresponding to those in the Earth’s inner core. This has been done for the hexagonal close packed and face entered cubic structures. The effects of alloying iron with magnesium and nickel on the equation of state as well on the elastic properties have been investigated. The calculations have shown that the hexagonal close packed structure in FeNi is more isotropic than the face-centered cubic structure, and that adding Mg to Fe has a large impact on the elastic properties. ?Finally, the effects of disorder due to thermal motion of the atoms have been investigated through ab-initio molecular dynamics simulations. Within the limits of this method and the setup, it is found that the face-centered cubic structure of molybdenum can be dynamically stabilized at high temperature, leading to a metastable structure, on the average. The dynamical stabilization of face-centered cubic molybdenum also rendered it possible to accurately calculate the lattice stability relative to the body-centered cubic phase. Inclusion of temperature effects for the lattice stability using ab-initio molecular dynamics simulations resolves the disagreement between ab-initio calculations and thermochemical methods. 

Ämnesord

Fasta tillståndets fysik  (sao)

Natural Sciences  (ssif)

Physical Sciences  (ssif)

Condensed Matter Physics  (ssif)

Naturvetenskap  (ssif)

Fysik  (ssif)

Den kondenserade materiens fysik  (ssif)

Natural Sciences  (ssif)

Physical Sciences  (ssif)

Other Physics Topics  (ssif)

Naturvetenskap  (ssif)

Fysik  (ssif)

Annan fysik  (ssif)

NATURAL SCIENCES  (svep)

Physics  (svep)

Condensed matter physics  (svep)

NATURVETENSKAP  (svep)

Fysik  (svep)

Kondenserade materiens fysik  (svep)

NATURAL SCIENCES  (svep)

Physics  (svep)

Other physics  (svep)

Computational physics  (svep)

NATURVETENSKAP  (svep)

Fysik  (svep)

Övrig fysik  (svep)

Beräkningsfysik  (svep)

Solid state physics  (LCSH)

Genre

government publication  (marcgt)

Indexterm och SAB-rubrik

Iron

Nickel

Magnesium

Manganese

Molybdenum

Zirconium

Elastic Constants

High pressure

Earth's core

Density-functional theory

Ab-initio

First-Principles

Core-level shifts

Molecular Dynamics

Phonons

Dynamical Instability

Iron

Uccg Fasta tillståndets fysik

Klassifikation

530.41 (DDC)

Uccg (kssb/8)