Microscopic investigation of the superconducting properties of the strongly coupled superconductor IrGe via mu SR

Exploring superconductors which can possess a pairing mechanism other than the BCS predicted s wave have continually attracted considerable interest. Superconductors with low-lying phonons may exhibit unconventional superconductivity as the coupling of electrons with these low-lying phonons can potentially affect the nature of the superconducting ground state, resulting in strongly coupled superconductivity. In this work, by using magnetization, AC transport, specific heat, and muon spin rotation/relaxation (mu SR) measurements, we report a detailed investigation on the superconducting ground state of the strongly coupled superconductor, IrGe, that has a transition temperature, T-C, at 4.7 K. Specific heat (SH), and transverse field mu SR is best described with an isotropic s-wave model with strong electron-phonon coupling, indicated by the values of both Delta(0)/k(B)T(C) = 2.3, 2.1 (SH,mu SR), and Delta C-el/gamma T-n(C) = 2.7. Zero-field mu SR measurements confirm the presence of time-reversal symmetry in the superconducting state of IrGe.