Dome-Shaped Superconducting Phase Diagram Linked to Charge Order in LaRu\(_{3}\)Si\(_{2}\)

The interplay between superconductivity and charge order is a central focus in condensed matter research, with kagome lattice systems offering unique insights. The kagome superconductor LaRu\(_{3}\)Si\(_{2}\) (\(T_{\rm c}\) \({\simeq}\) 6.5 K) exhibits a hierarchy of charge order transitions: primary (\(T_{\rm co,I}\) \({\simeq}\) 400 K), secondary (\(T_{\rm co,II}\) \({\simeq}\) 80 K), and an additional transition at (\(T^{*}\) \(\simeq\) 35 K). The transitions at \(T_{\rm co,II}\) and \(T^{*}\) are linked to electronic and magnetic responses as revealed by muon-spin rotation and magnetotransport experiments. However, the connection between superconductivity, charge order, and electronic responses has remained elusive. By employing magnetotransport and X-ray diffraction techniques under pressures of up to 40 GPa, we observe that \(T_{\rm c}\) rises to 9 K at 2 GPa, remains nearly constant up to 12 GPa, and then decreases to 2 K at 40 GPa, resulting in a dome-shaped phase diagram. The resistivity anomaly at \(T^{*}\) and magnetoresistance also exhibit a similar dome-shaped pressure dependence. Furthermore, we find that charge order transitions from long-range to short-range above 12 GPa, correlating with the suppression of \(T_{\rm c}\), suggesting superconductivity is closely tied to the charge-ordered state. Specifically, \(T_{\rm c}\) peaks when charge order and the normal-state electronic responses are optimized. In contrast to systems like the cuprates, transition metal dichalcogenides, and other kagome materials, where superconductivity typically competes with charge order, LaRu\(_{3}\)Si\(_{2}\) displays a pronounced interdependence between these two phenomena. This distinctive behavior sheds new light on the connection between superconductivity and charge order, offering avenues for theoretical advancements in understanding superconductivity.