Sökning: "density functional theory dft"

Visar resultat 1 - 5 av 58 uppsatser innehållade orden density functional theory dft.

  1. 1. Implementation of Dyson equation to accelerate convergence in RS-LMTO-ASA code

    Master-uppsats, Uppsala universitet/Materialteori

    Författare :Elis Uebel; Viktor Frilén; [2024]
    Nyckelord :Density functional theory; Dyson equation;

    Sammanfattning : First-principle calculations is a key ingredient for us to understand, improve and design new materials. Density functional theory (DFT) [1] has proven to be a very powerful tool and a number of different versions exist depending on the problem at hand. LÄS MER

  3. 2. First principles investigation of the thermal conductivity of Zr, ZrC, and ZrN

    Master-uppsats, KTH/Fysik

    Författare :Daniel Karlsson; [2023]
    Nyckelord :Electron-phonon interaction; Density functional theory; Boltzmann transport equation; first-principles; thermal conductivity; electrical resistivity; Abinit; Phono3py; Elektron-fononväxelverkan; täthetsfunktionalteori; Boltzmanns transportekvation; värmeledningsförmåga; elektrisk resistivitet; Abinit; Phono3py;

    Sammanfattning : The thermal conductivity and electrical resistivity of Zr, ZrC, and ZrN were calculated using first-principles density functional theory (DFT) and the Boltzmann transport equation. The electron-phonon scattering was modeled via the self-energy relaxation time approximation (SERTA), and the phonon-phonon scattering via the analogous single-mode relaxation time approximation (SMRTA). LÄS MER

  4. 3. Theoretical investigation of α-iron chromium carbide (α-Fe/Cr7C3) interfaces

    Master-uppsats, Malmö universitet/Institutionen för materialvetenskap och tillämpad matematik (MTM)

    Författare :Hussein Al-Hussein; [2023]
    Nyckelord :Alpha-iron; Chromium carbide; Cr7C3; Fe; Theoretical investigation; Orthorhombic; X-ray diffraction pattern; XRD; VASP; VESTA; Body-centered-cubic; Ferrite; Density functional theory; DFT; Surface relaxation; Simulation; Calculation; Energy relaxation; Slab models; Coherency; Surface energy; Interfacial energy; Alfa-järn; Kromkarbid; Cr7C3; Fe; Teoretisk undersökning; Ortorombisk; Röntgendiffraktion; XRD; VASP; VESTA; Ytenergi; Koherent; Simulering; Beräkning; Järnkarbid; DFT; Täthetsfunktionalanalys;

    Sammanfattning : This master thesis presents a theoretical investigation of the energy and stability of interfaces in iron-carbide compounds, specifically focusing on the α-Fe/Cr7C3 system. The study aims to fill the gap in knowledge regarding the surface energetics of these interfaces using Density Functional Theory (DFT). LÄS MER

  5. 4. Photophysics of the polymer acceptor PF5-Y5 in organic photovoltaics : A first principles theory based study

    Master-uppsats, Karlstads universitet/Institutionen för ingenjörsvetenskap och fysik (from 2013)

    Författare :Anton Almén; [2022]
    Nyckelord :PF5-Y5; Non-fullerene-acceptor; NFA; polymer; fundamental; optical; gap; oxidation; reduction; exciton; binding; energy; oligomer; length; PF5-Y5; Non-fullerene-acceptor; NFA; polymer; fundamentalt; optiskt; gap; oxidation; reduktion; exciton; binding; energi; oligomerlängd;

    Sammanfattning : Non-fullerene Acceptors (NFAs) have gathered a great deal of interest for use inorganic photovoltaics (OPVs) due to recent breakthroughs in their power conversion efficiency and other advantages they offer over their Fullerene-based counterparts. In this work, a new promising non-fullerene polymer acceptor, PF5-Y5, have been studied using density functional theory and time-dependent density functional theory; and the effects that oligomer length, geometry relaxation and exchange-correlation interaction has on the exciton binding energies (the difference between optical and fundamental energy gaps) have been investigated. LÄS MER

  7. 5. Symmetry Analysis of Orbitals in a Plane Wave Basis : A Study on Molecules and Defects in Solids

    Master-uppsats, Linköpings universitet/Teoretisk Fysik

    Författare :William Stenlund; [2022]
    Nyckelord :Point Defect; Divacancy; Symmetry; Group Theory; DFT; Plane Wave; Plane Wave Basis; 4H-SiC;

    Sammanfattning : Modeling and analysing materials with theoretical tools is of great use when finding new systems for applications, for example, semiconductors with point defects can be used for quantum applications, like single photon emitters. One important aspect to consider symmetry, which can yield useful information about the properties of a system. LÄS MER