Creating superconductivity in WB<sub>2</sub> through pressure-induced metastable planar defects.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36550110.
- Also identified by DOI 10.1038/s41467-022-35191-8 and PMC identifier 9780245.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
High-pressure electrical resistivity measurements reveal that the mechanical deformation of ultra-hard WB<sub>2</sub> during compression induces superconductivity above 50 GPa with a maximum superconducting critical temperature, T<sub>c</sub>of 17 K at 91 GPa. Upon further compression up to 187 GPa, the T<sub>c</sub>gradually decreases. Theoretical calculations show that electron-phonon mediated superconductivity originates from the formation of metastable stacking faults and twin boundaries that exhibit a local structure resembling MgB<sub>2</sub> (hP3, space group 191, prototype AlB<sub>2</sub>). Synchrotron x-ray diffraction measurements up to 145 GPa show that the ambient pressure hP12 structure (space group 194, prototype WB<sub>2</sub>) continues to persist to this pressure, consistent with the formation of the planar defects above 50 GPa. The abrupt appearance of superconductivity under pressure does not coincide with a structural transition but instead with the formation and percolation of mechanically-induced stacking faults and twin boundaries. The results identify an alternate route for designing superconducting materials.