Superconductivity up to 14.2 K in MnB₄ Under Pressure.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Chemistry

Background:

• Superconductivity in 3d transition-metal compounds is rare, particularly for manganese-based materials.
• Limited stoichiometric manganese compounds exhibit superconductivity, highlighting a gap in materials discovery.

Purpose of the Study:

• To report the discovery of superconductivity in a novel manganese-based compound, MnB4.
• To investigate the effect of high pressure on the superconducting properties and structural behavior of MnB4.
• To explore the potential of combining 3d-transition metals with light elements for high-temperature superconductivity.

Main Methods:

• Synthesis and characterization of MnB4.
• High-pressure experiments to induce and study superconductivity.
• Synchrotron X-ray diffraction for structural analysis under pressure.
• Theoretical calculations to support experimental findings.

Main Results:

• Superconductivity observed in MnB4 with an onset transition temperature up to 14.2 K, the highest for stoichiometric Mn-based superconductors.
• High pressure (≈30 GPa) suppresses weak semiconducting behavior and induces superconductivity.
• Superconducting transition temperature (Tc) increases with pressure, reaching ≈14.2 K at 150 GPa.
• Monoclinic crystal structure (S.G: P21/c) remains unchanged, but an unusual crossover of lattice parameters b and c is observed under pressure.

Conclusions:

• MnB4 represents a significant advancement in the search for manganese-based superconductors.
• High pressure is a viable tuning parameter to enhance superconductivity in this material.
• The combination of magnetic 3d-transition metals and light elements offers a promising avenue for discovering high Tc superconductors.