Recently a new family of Cr-based ${\mathrm{A}}_2{\mathrm{Cr}}_3{\mathrm{As}}_3$ ($A=\text{K}$, Rb, Cs) superconductors was reported, which own a rare quasi-one-dimensional (Q1D) crystal structure with infinite ${\left({\mathrm{Cr}}_3{\mathrm{As}}_3\right)}^{2-}$ chains and exhibit intriguing superconducting characteristics possibly derived from spin-triplet electron pairing. The crystal structure of ${\mathrm{A}}_2{\mathrm{Cr}}_3{\mathrm{As}}_3$ is actually a slight variation of the hexagonal ${\mathrm{TlFe}}_3{\mathrm{Te}}_3$ prototype, although they have different lattice symmetry. Here we report superconductivity in a 133-type ${\mathrm{KCr}}_3{\mathrm{As}}_3$ compound that belongs to the latter structure. The single crystals of ${\mathrm{KCr}}_3{\mathrm{As}}_3$ were prepared by the deintercalation of K ions from ${\mathrm{K}}_2{\mathrm{Cr}}_3{\mathrm{As}}_3$ crystals which were grown from a high-temperature solution growth method, and it owns a centrosymmetric lattice in contrast to the noncentrosymmetric ${\mathrm{K}}_2{\mathrm{Cr}}_3{\mathrm{As}}_3$. After annealing at a moderate temperature, the ${\mathrm{KCr}}_3{\mathrm{As}}_3$ crystals show superconductivity at 5 K revealed by electrical resistivity, magnetic susceptibility, and heat capacity measurements. The discovery of this ${\mathrm{KCr}}_3{\mathrm{As}}_3$ superconductor provides a different structural instance to study the exotic superconductivity in these Q1D Cr-based superconductors.

• Received 14 August 2017
• Revised 19 September 2017

DOI:https://doi.org/10.1103/PhysRevB.96.140504