Superconductivity up to 37.6 K in compressed scandium

Abstract

The pursuit of elemental superconductors with high critical temperature (T_{c}) holds immense scientific significance due to their relatively simple material composition, which not only aids in understanding the mechanisms of superconductivity but also facilitates further exploration of high-temperature superconductors in compound materials. Here, we report experimental findings of superconductivity for scandium (Sc) in the pressure range of 64 GPa to 261 GPa. As a result, the highest T_{c} of 37.6 K observed in Sc-V phase at 243 GPa sets the current record among all elements. An estimate based on the Ginzburg-Landau model gives a zero-temperature upper critical magnetic field of 21.3 T with a coherence length of 39.3 Å. Current-voltage measurements show that the zero-temperature critical current and its density can reach 0.146 A and 70 A mm^{−2} of Sc-IV at 198 GPa, and 0.116 A and 50 A mm^{−2} of Sc-V at 250 GPa, respectively. Further theoretical calculations show that pressure-induced phonon softening plays a key role in increasing T_{c} upon compression. Our current findings shed light on the understanding of high superconductivity in simple elements and provide insight into exploring high-T_{c} elemental superconductors and Sc-based superconductors.