Multigap electron-phonon superconductivity in the quasi-one-dimensional pnictide K2Mo3As3

We show, using density functional calculations, that quasi-one-dimensional ${\mathrm{K}}₂{\mathrm{Mo}}₃{\mathrm{As}}₃$, which is closely related to ${\mathrm{K}}₂{\mathrm{Cr}}₃{\mathrm{As}}₃$ and has very similar superconducting properties, is not close to magnetism and has conventional $s$ wave electron-phonon superconductivity. This superconductivity is of multigap character due to different coupling on different Fermi surface sheets. This is discussed in relation to the properties of this family of quasi-one-dimensional pnictide superconductors. The results show that this family of superconductors provides a unique opportunity for studying the interplay of spin fluctuations and electron-phonon superconductivity in transition metal pnictides, and offer a path for sorting out the different proposed superconducting scenarios in this fascinating family of pnictide superconductors.