Motivated by recent thermal conductivity measurements in the superconductor ${\mathrm{CeCoIn}}_5$, we theoretically examine a possible staggered spin-triplet superconducting order to be induced by the coupled spin-density-wave (SDW) and $d$-wave superconducting (SC) orders in the high-field and low-temperature (HFLT) SC phase peculiar to this material with strong paramagnetic pair-breaking (PPB). It is shown that one type of the $\pi$-triplet order is consistent with that explaining the thermal conductivity data and can naturally be incorporated in the picture that the HFLT phase is a consequence of the strong PPB effect inducing the SDW order and the FFLO spatial modulation parallel to the applied magnetic field.

• Received 1 March 2017
• Revised 16 May 2017

DOI:https://doi.org/10.1103/PhysRevB.95.224513