Ab initio investigation of superconductivity in noncentrosymmetric Ca₃Ir₄Ge₄

Abstract

Ab initio pseuduopotential calculations are made to investigate structural, electronic, vibrational and superconducting properties of the recently discovered noncentrosymmetric . Even without the inclusion of the spin–orbit interaction, this material is found to be a BCS superconductor, with a medium strength average electron–phonon coupling parameter . The largest contribution (94%) to this parameter comes from the interaction of electrons near the Fermi level from Ir 6p, Ge 4p and Ca 3d states with the acoustic and optical phonon modes up to 5.8 THz. With an acceptable choice for effective screened Coulomb repulsion parameter, the superconducting transition temperature  K is obtained, in good agreement with a recent experimental study.

Keywords:

• electronic properties
• lattice dynamics
• phonons
• superconductivity
• vibrational properties
• density-functional theory

Acknowledgements

The calculations were performed using the Intel Nehalem (i7) cluster (ceres) at the University of Exeter.

Notes

No potential conflict of interest was reported by the authors.