New superconducting material discovered in transition-metal dichalcogenides materials

With the support of electrical transport and magnetic measurement systems of Steady High Magnetic Field Facility (SHMFF), a research team from Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS), discovered a new superconducting material called (InSe₂)_xNbSe₂, which possesses a unique lattice structure. The superconducting transition temperature of this material reaches 11.6 K, making it the transition metal sulfide superconductor with the highest transition temperature under ambient pressure.

The results were published in Journal of the American Chemical Society.

TMD materials have received lots of attention due to the numerous applications in the fields of catalysis, energy storage, and integrated circuit. However, the relatively low superconducting transition temperatures of TMD superconductors have limited their potential use.

In this study, scientists successfully fabricated a new superconducting material with the chemical formula (InSe₂)_xNbSe₂. Unlike the conventional conditions where isolated atoms are inserted into the van de Waals gaps of low dimensional materials, in (InSe₂)_xNbSe₂ the intercalated indium atoms were found to form InSe₂-bonded chains.

"This material has very high transition temperature among all transition metal dichalcogenide (TMD) superconductors," said Prof. ZHANG Changjin, who led the team, "and it exhibits an impressive critical current density."

The superconducting transition temperature of the (InSe₂)_0.12NbSe₂ sample could be as high as 11.6 K at ambient pressure, which is 60% higher than that of pristine NbSe₂.

Furthermore, the (InSe₂)_xNbSe₂ superconductor exhibits large critical current density of 8x10⁵ A/cm₂, which is also the highest among all TMD superconductors. The critical current density is comparable with high temperature superconductors such as cuprate and iron-based compounds, demonstrating its good application prospects.

This discovery opens up new possibilities for advancing superconductivity research and developing high-temperature superconductors with improved performance, according to the team.