Possible collective spin excitation in the spin-triplet superconducting state of SrRuO; Multi-band theory

Nomura, Takuji; Hirashima, Dai*; Yamada, Kosaku*

We investigate possible collective spin excitation by calculating the dynamical spin susceptibility in the spin-triplet superconducting state of SrRuO. The effect of the fluctuating triplet-pairing condensate on the spin susceptibility is taken into account. The triplet pairing symmetry is assumed to be the most promising form: () ( + . For small (maybe realistic) anisotropy of pairing interaction in spin space, we expect a possible low-energy spin-wave mode as a peak structure in the imaginary part of the dynamical spin susceptibility, isolated from the spin excitation continuum. The present work is a natural extension of previous single-band calculations to a more realistic three-band calculation.