Sökning: "Configurational disorder"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Configurational disorder.

1. 1. Configurational and Magnetic Interactions in Multicomponent Systems

   Författare :Björn Alling; Igor A. Abrikosov; Lars Hultman; Stefan Blügel; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic interactions; Configurational thermodynamics; Curie temperature; theoretical physics; magnetism; TiAlN; TiN; AlN; CrN; TiCrN; nitrides; NiMnSb; NiCuMnSb; Heusler alloys; spintronics; half-metallic; spinodal decomposition; first-principles; ab-initio; Magnetism; Magnetism;

   Sammanfattning : This thesis is a theoretical study of configurational and magnetic interactions in multicomponent solids. These interactions are the projections onto the configurational and magnetic degrees of freedom of the underlying electronic quantum mechanical system, and can be used to model, explain and predict the properties of materials. LÄS MER

3. 2. Disordered Icosahedral Boron-Rich Solids : A Theoretical Study of Thermodynamic Stability and Properties

   Författare :Annop Ektarawong; Björn Alling; Michael Widom; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Icosahedral boron-rich solids; Boron carbide; Configurational disorder; First-principles calculations; Thermodynamic stability; Superatom-special quasirandom structure;

   Sammanfattning : This thesis is a theoretical study of configurational disorder in icosahedral boron-rich solids, in particular boron carbide, including also the development of a methodological framework for treating configurational disorder in such materials, namely superatom-special quasirandom structure (SA-SQS). In terms of its practical implementations, the SA-SQS method is demonstrated to be capable of efficiently modeling configurational disorder in icosahedral boron-rich solids, whiles the thermodynamic stability as well as the properties of the configurationally disordered icosahedral boron-rich solids, modeled from the SA-SQS method, can be directly investigated, using the density functional theory (DFT). LÄS MER

4. 3. First-principles study of configurational disorder in icosahedral boron-rich solids

   Författare :Annop Ektarawong; Björn Alling; Sergei Simak; Lars Hultman; Biplab Sanyal; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis is a theoretical study of configurationally disordered icosahedral boronrich solids, in particular boron carbides, using density functional theory and alloy theory. The goal is to resolve discrepancies, regarding the properties of boron carbides, between experiments and previous theoretical calculations which have been a controversial issue in the field of icosahedral boron-rich solids. LÄS MER

5. 4. Theoretical studies of the coupling between electronic, vibrational, configurational and structural effects in metal borides

   Författare :Erik Johansson; Björn Alling; Johanna Rosén; Paul Erhart; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis addresses theoretical studies of the coupling between electronic, vibrational, configurational and structural degrees of freedom in metal borides. The effect of external conditions of temperature, pressure and composition on the interplay between internal degrees of freedom is investigated. LÄS MER

7. 5. Vibrations in solids : From first principles lattice dynamics to high temperature phase stability

   Författare :Nina Shulumba; Magnus Odén; Igor Abrikosov; Frank Mücklich; Matteo Calandra; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this thesis I introduce a new method for calculating the temperature dependent vibrational contribution to the free energy of a substitutionally disordered alloy that accounts for anharmonicity at high temperatures. This method exploits the underlying crystal symmetries in an alloy to make the calculations tractable. LÄS MER