Interplay of Superconductivity and Fermi-Liquid Transport in Rh-Doped CaFe2As2 with Lattice-Collapse Transition

Ca(Fe₁₋ₓRhₓ)₂As₂ undergoes successive phase transitions with increasing Rh doping in the T $=$ 0 limit. The antiferromagnetic-metal phase with orthorhombic structure at 0.00 ≤ x ≤ 0.020 is driven to a superconducting phase with uncollapsed-tetragonal (ucT) structure at 0.020 ≤ x ≤ 0.024; a non-superconducting collapsed-tetragonal (cT) phase takes over at x ≥ 0.024. The breakdown of Fermi-liquid transport is observed in the ucT phase above Tc. In the adjacent cT phase, Fermi-liquid transport is restored along with a disappearance of superconductivity. This interplay of superconductivity and Fermi-liquid transport suggests the essential role of magnetic fluctuations in the emergence of superconductivity in doped CaFe₂As₂.