Record-high-Tc elemental superconductivity in scandium

TL;DR

Applying high pressure to elemental scandium significantly increases its superconducting critical temperature to a record 36 K, revealing multiple phase transitions and strong electron-phonon coupling, advancing the search for high-Tc elemental superconductors.

Contribution

This work demonstrates a record-high Tc in elemental scandium under high pressure and elucidates the underlying phase transitions and electron-phonon interactions involved.

Findings

Tc reaches 36 K at high pressure in scandium

Multiple phase transitions occur in scandium under pressure

Strong electron-phonon coupling enhances superconductivity

Abstract

Elemental materials provide clean and fundamental platforms for studying superconductivity. However, the highest superconducting critical temperature (Tc) yet observed in elements has not exceeded 30 K. Discovering elemental superconductors with a higher Tc is one of the most fundamental and challenging tasks in condensed matter physics. In this study, by applying high pressure up to approximately 260 GPa, we demonstrate that the superconducting transition temperature of elemental scandium (Sc) can be increased to 36 K, which is a record-high Tc for superconducting elements. The pressure dependence of Tc implies the occurrence of multiple phase transitions in Sc, which is in agreement with previous X-ray diffraction results. Optimization of Tc is achieved in the Sc-V phase, which can be attributed to the strong coupling between d electrons and moderate-frequency phonons, as suggested by our first-principles calculations. This study provides insights for exploring new high-Tc elemental metals.