PuPt2In7: a computational and experimental investigation

Flux-grown single crystals of PuPt${}_2$In${}_7$ are characterized and found to be both non-superconducting and non-magnetic down to 2 K. The Sommerfeld specific heat coefficient of $\sim 250$ mJ/mol K${}^2$ indicates heavy fermion behavior. We report the results of generalized gradient approximation (GGA)+$U$ calculations of PuPt${}_2$In${}_7$ and as yet unsynthesized isovalent PuPt${}_2$Ga${}_7$. The strength of the $c$-$f$ hybridization of PuPt${}_2$In${}_7$ is similar to the PuCoIn${}_5$ superconductor. The bare and $f$-weighted susceptibility within the constant-matrix-element approximation is calculated, showing a maximum along the $q_z$ direction at $q_x=q_y=0.5$. A similar and slightly stronger maximum is also found in the structurally related heavy-fermion materials PuCoGa${}_5$ and PuCoIn${}_5$. The absence of superconductivity in PuPt${}_2$In${}_7$ is examined based on the results of our calculations.