Crossover between Fermi liquid and non-Fermi liquid behavior in the non-centrosymmetric compound Yb2Ni12P7

A crossover from a non-Fermi liquid to a Fermi liquid phase in Yb2Ni12P7 is observed by analyzing electrical resistivity ρ(T), magnetic susceptibility χ(T), specific heat C(T), and thermoelectric power S(T) measurements. The electronic contribution to specific heat, Ce(T), behaves as Ce(T)/T ∼ −ln(T) for 5 K < T < 15 K, which is consistent with non-Fermi liquid behavior. Below T ∼ 4 K, the upturn in Ce(T)/T begins to saturate, suggesting that the system crosses over into a Fermi-liquid ground state. This is consistent with robust ρ(T) − ρ0 = AT2 behavior below T ∼ 4 K, with the power-law exponent becoming sub-quadratic for T > 4 K. A crossover between Fermi-liquid and non-Fermi liquid behavior suggests that Yb2Ni12P7 is in close proximity to a quantum critical point, in agreement with results from recent measurements of this compound under applied pressure.