Superconductivity of cerium at quasihydrostatic pressure up to 54 GPa

Abstract

Cerium is a fascinating element due to its diverse physical properties, which include forming various crystal structures ($\ensuremath{\gamma}, \ensuremath{\alpha}, {\ensuremath{\alpha}}^{\ensuremath{'}}, {\ensuremath{\alpha}}^{\ensuremath{'}\ensuremath{'}}$, and $\ensuremath{\epsilon}$), 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 quasihydrostatic pressures up to 54 GPa. Upon applying pressure, cerium undergoes the $\ensuremath{\alpha}\phantom{\rule{4pt}{0ex}}\ensuremath{\rightarrow}\phantom{\rule{4pt}{0ex}}{\ensuremath{\alpha}}^{\ensuremath{'}\ensuremath{'}}$ transition at around 4.9 GPa, which is accompanied by the appearance of superconductivity with ${T}_{\mathrm{c}}$ of 0.4 K, and ${T}_{\mathrm{c}}$ slightly increases to 0.5 K at 11.4 GPa. At 14.3 GPa, ${T}_{\mathrm{c}}$ suddenly increases when the ${\ensuremath{\alpha}}^{\ensuremath{'}\ensuremath{'}}$ phase transforms into the $\ensuremath{\epsilon}$ phase, reaching a maximum value of 1.25 K at around 17.2 GPa. Upon further increasing the pressure, ${T}_{\mathrm{c}}$ 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.