Electronic and dynamic properties of XGe3 (X=Be, Mg, Ca, Sr, Ba)compounds

In this thesis study, the structural, mechanical, vibrational and thermodynamic properties of XGe3 (X=Be, Mg, Ca, Sr, Ba) compounds in tetragonal and hexagonal phases were calculated with the density functional theory. While making the calculations, the electron-ion interaction was handled with the PAW method, and the electron-electron interaction was handled with the PBE parameterization. The obtained lattice parameters from geometric optimization were found to be consistent with existing results. Electronic band structure and density of states curves for these compounds were plotted and interpreted. Elastic constants were calculated using the stress-strain method, and polycrystalline properties for mechanically stable compounds were also calculated and examined in detail. Minimum thermal conductivity values were also calculated. Additionally, phonon dispersion and phonon density of states were drawn and their dynamic stability was investigated. The thermodynamic properties of dynamically stable compounds were also analyzed.