In most manganese-based chalcogenides, superconductivity only appears under high pressure and disappears once the pressure is released, because the key orthorhombic B31 structure is not stable at ambient conditions.

In a study published in Advanced Materials, a research team led by Prof. WANG Xianlong and Dr. WANG Pei from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences successfully stabilized a B31-type MnSe_0.5Te_0.5 phase that exhibits superconductivity driven by pressure-induced Jahn-Teller distortions.

Researchers partially replaced selenium with tellurium in MnSe. This substitution increased the energy barrier for the reverse structural transition during decompression, effectively "locking in" the high-pressure B31 phase.

As a result, superconductivity emerged at around 16 GPa during compression and could still be observed down to about 4 GPa during pressure release. In this pressure range, weak antiferromagnetic correlations also reappeared and coexisted with superconductivity. The unusual path-dependent behavior was believed to be linked to disorder-related quantum critical fluctuations rather than conventional spin fluctuations.

Researchers attributed the emergence of superconductivity to pressure-induced Jahn–Teller distortions which trigger a Peierls-like Mn–Mn dimerization. This structural change acts as a key ingredient for superconductivity by reshaping the electronic structure and enabling Cooper pair formation. At the same time, it helps stabilize the high-pressure phase over a wider pressure range.

This work demonstrates a chemical strategy to stabilize high-pressure superconducting phases at lower pressures, and suggests a possible way to retain metastable states under ambient conditions for future applications.