Superconductivity of cerium under pressures up to 54GPa

Abstract

Cerium is a fascinating element due to its diverse physical properties, which include forming various crystal structures ($γ$, $α$, $α^{'}$, $α^{''}$ and $ε$), mixed valence behavior and superconductivity, making it an ideal platform for investigating the interplay between different electronic states. Here, we present a comprehensive transport study of cerium under hydrostatic pressures up to 54 GPa. Upon applying pressure, cerium undergoes the $α$ $\rightarrow$ $α^{''}$ transition at around 4.9 GPa, which is accompanied by the appearance of superconductivity with $T_{\rm c}$ of 0.4 K, and $T_{\rm c}$ slightly increases to 0.5 K at 11.4 GPa. At 14.3 GPa, $T_{\rm c}$ suddenly increases when the $α^{''}$ phase transforms into the $ε$ phase, reaching a maximum value of 1.25 K at around 17.2 GPa. Upon further increasing the pressure, $T_{\rm c}$ monotonically decreases. Together with the results of previous studies, our findings suggest that the evolution of superconductivity in cerium is closely correlated with the multiple pressure-induced structural transitions and corresponding unusual electronic structures.