Investigation of the structural, electronic and superconductivity properties of Ta3Ge compound

The structural, elastic, electronic, dynamical and superconducting properties of A15 type Ta3Ge have been investigated by using the density functional theory as implemented in Quantum-Espresso simulation package in this thesis. The calculations related to elastic and electronic properties of Ta3Ge predict that this compound is ductile in natüre and shows metallic features. The electronic properties also show that the Ta 5d states of Ta3Ge mainly contribute to the electronic density of states very close to the Fermi level. According to the dynamical properties, there is no gap in the calculated phonon dispersion graph for Ta3Ge, although there is a large mass difference between Ta and Ge atoms. It is also interesting that the vibrations of Ta atoms play a dominant role in the formation of the highest optical phonon mode. The average electron-phonon coupling parameter is calculated as 1.083 and using this value, the superconducting transition temperature (Tc) is estimated to be 8.392 K for Ta3Ge. This Tc value is in very good agreement with the experimental value of 8 K which is previously measured for Ta3Ge prepared as thin film. Keywords: Ta3Ge, A15 phase, Structural properties, Electronic properties, Dynamical properties, Superconducting properties