Description
Quantum criticality has become a central paradigm for understanding unconventional superconductivity. However, its manifestation in the newly discovered family of nickelates remains largely unexplored. In this work, we investigate the thermopower-to-temperature ratio ($S/T$) in parent NdNiO$_{2}$ (NNO) and Sm$_{0.95-x}$Ca$_{0.05}$Eu$_{x}$NiO$_{2}$ (SCE$_{x}$) films. In clean NNO samples, the opposite signs of $S/T$ and Hall coefficient ($R_{H}$) indicate that thermopower are dominated by quantum criticality rather than band theory. In SCE$_{x}$, a log$T$ dependence emerges once superconductivity is suppressed by a magnetic field, but deviates from this behavior at $T_{s}$. The positive correlation between $T_{s}$ and $T_{c}$ highlights the role of quantum critical behavior in nickelate superconductors. These findings emphasize the importance of quantum critical behavior in proximity to QCP in infinite-layer nickelates and further suggest a convergence of such behavior across different unconventional superconducting families.
