Abrupt recovery of Fermi-liquid transport by the c-axis collapse in CaFe2(As1-xPx)2 single crystals

Single crystals of CaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ are found to exhibit the tetragonal (T) to collapsed-tetragonal (cT) transition at $T_{\rm cT} \lesssim100$Kfor$x>0.05$\mathrm{.}Thec-axisshrinksby$\sim9$$T_{\rm cT}$, which substantially diminishes the interband nesting between the hole and electron bands. In sharp contrast to the superconducting T phase of $A$Fe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ ($A=$ Ba, Sr), where the anomalous non-Fermi liquid transport properties are observed, the resistivity, Hall coefficient, and magnetoresistance data in the Ca-based system all indicate that the standard Fermi liquid behaviors are recovered abruptly below $T_{\mathrm{c}\mathrm{T}}$, and the superconductivity disappears completely. The intimate link between the superconductivity and the non-Fermi liquid transport enlightens the essential role of interband-associated fluctuation effects in Fe-pnictides.