Strong orbital fluctuations in multipolar ordered states of PrV2Al20
Abstract Pr T 2 Al 20 T =Ti, V) are ideal systems to study the quadrupole Kondo effect and quantum criticality arising from orbital degrees of freedom. The both systems have the nonmagnetic cubic G 3 crystal electric field ground doublet with the well separated excited state. In particular, PrV 2 Al 20 exhibits anomalous metallic behavior above and below the multipolar ordering temperatures, reflecting the even stronger hybridization between f and conduction electrons possibly due to a proximity to an orbital quantum critical point. Here we report the anomalous metallic behaviors found in a pure single crystal of PrV 2 Al 20 Our detailed analyses revealed that the resistivity indicates power law temperature dependence proportional to T 3 Furthermore, we pointed out that the 4 f electron contribution to the specific heat also exhibits power law behavior proportional to T 4 Both observations are in a sharp contrast to the gapped behavior found in PrTi 2 Al 20 and indicate the strong c f hybridization and strong orbital fluctuations in PrV 2 Al 20 In addition, the 4 f electron contribution to the entropy in PrV 2 Al 20 reaches only 50% of R ln 2 at an orbital ordering at T =0.75 K, suggesting another 50% of R ln 2 expected for G 3 doublet is already released at higher temperature possibly due to quadrupole Kondo effect.