Recent research guided by Prof. Xianhui Chen of the Chinese Academy of Sciences’ (CAS) University of Science and Technology of China (USTC) and Prof. Jian Sun of Nanjing University achieved a new high superconducting transition temperature of 36 K in elemental materials under high pressure. The findings were published in the journal Physical Review Letters.
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Elemental materials offer pristine and fundamental platforms for investigating superconductivity. Over 50 elements have been found to exhibit superconductivity under atmospheric conditions or high pressures since the discovery of superconductivity in the element mercury by the Dutch scientist Onis in 1911.
Although most elements have low superconducting critical temperatures (Tc), elemental titanium (Ti) at high pressures had the highest previous elemental Tc of 26 K.
According to earlier research, under pressure, elemental scandium (Sc) goes through four structural phase transitions. The superconductivity of elemental Sc at higher pressures remains a mystery, despite the limitations of early high-pressure experimental techniques.
Researchers investigated the transport of elemental Sc at extremely high pressures and identified its superconducting phase diagram. High voltage electrical transport measurements found that Tc increased quickly with increasing pressure in the Sc-II phase, consistent with earlier reports.
Additionally, using first-principles calculations to investigate the physical cause of the significant increase in superconducting Tc at high pressure, researchers discovered that the Sc-V phase’s strong coupling between d electrons and moderate-frequency phonons is the primary cause of its high Tc.
The research findings suggested a close relationship between the structure and the Tc of elemental Sc under pressure. The 36 K Tc discovered in the Sc-V phase not only sets a new elemental Tc record, but also gives insight on the discovery of high-temperature superconducting materials in simple systems.
Ying, J. J., et al. (2023). Record High 36 K Transition Temperature to the Superconducting State of Elemental Scandium at a Pressure of 260 GPa. Physical Review Letters. doi.org/10.1103/physrevlett.130.256002.