Zero-Field Quantum Critical Point in Ce${}_{0.91}$Yb${}_{0.09}$CoIn${}_5$

Abstract

We present results of specific heat, electrical resistance, and magnetoresistivity measurements on single crystals of the heavy-fermion superconducting alloy Ce${}_{0.91}$Yb${}_{0.09}$CoIn${}_5$. Non-Fermi liquid to Fermi liquid crossovers are clearly observed in the temperature dependence of the Sommerfeld coefficient ${\hat{I}}^3$ and resistivity data. Furthermore, we show that the Yb-doped sample with $x=0.09$ exhibits universality due to an underlying quantum phase transition without an applied magnetic field by utilizing the scaling analysis of ${\hat{I}}^3$. Fitting of the heat capacity and resistivity data based on existing theoretical models indicates that the zero-field quantum critical point is of antiferromagnetic origin. Finally, we found that at zero magnetic field the system undergoes a third-order phase transition at the temperature $T_{c3}\approx 7$ K.

5 pages + 3 figures (main text) & 5 pages + 4 figures (supplementary materials)