Crystal growth and composition-property relationship of Ce₃ Pd₂₀ Si₆ single crystals

To elucidate the discrepancies in low-temperature data reported on the quantum critical heavy fermion compound Ce3 Pd20 Si6 and reveal the compound's intrinsic properties, single crystals of varying stoichiometry were grown by various techniques-from the melt and from high-temperature solutions using fluxes of various compositions. The resulting stoichiometry of the crystals as well as their physical properties show sizable dependence on the different growth techniques. The Ce content ΔCe varies by more than 3 at.% among all grown single crystals. We have revealed a systematic dependence of the residual resistance ratio, the lattice parameter, the (lower) phase-transition temperature TL, and the maximum in the temperature dependent electrical resistivity Tmax with ΔCe. This clarifies the sizable variation in the values of TL reported in the literature. We discuss the physical origin of the observed composition-property relationship in terms of a Kondo lattice picture. We predict that a modest pressure can suppress TL to zero and thus induce a quantum critical point.