Conventional s-Wave Superconductivity in Noncentrosymmetric Ir2Ga9

Superconductivity without spatial inversion symme- try has begun to attract much attention since the dis- covery of the superconductor CePt3Si.1 It is presumed that the absence of spatial inversion symmetry causes an admixture between even and odd parities of super- conducting pairing due to antisymmetric spin-orbit cou- pling (ASOC).2 However, there has been no clear evi-