Probing the physical and superconducting properties of hexagonal ZrRuAs: A first-principles calculation

In this thesis, in order to find out the underlying mechanism of superconductivity in ZrRuAs with the hexagonal ZrNiAl-type layer crystal structure, ab initio pseudopotential calculations have been realized on its structural, electronic, elastic, mechanical, phonon and electron-phonon interaction properties. In the vicinity of the Fermi level, Ru 4d and Zr 4d states dominate and mainly contribute to the conduction properties of ZrRuAs, A critical assessment of elastic and mechanical properties for ZrRuAs reveals that this superconductor is soft (ductile) due to remarkable metallic bonding. Phonon anomalies have been observed in the phonon spectrum of ZrRuAs for the lowest transverse acoustic branch and low-frequency transverse optical branches along the Γ-K and Γ-M-K symmetry directions. Therefore, these phonon branches play an important role in the formation of superconducting state for ZrRuAs since their phonon anomalies considerably increase their electron-phonon coupling parameters. Our electron-phonon interaction calculations reveal that ZrRuAs is a conventional phonon-mediated superconductor with strong electron-phonon coupling parameter of 1,32 in which Ruthenium is considered to be more dominant element in determining the development of superconducting. The strong electron-phonon coupling parameter of ZrRuAs produces its superconducting transition temperature to be 11,12 K which accord well with its experimental values of 12 K.