Creating superconductivity in WB2 through pressure-induced metastable planar defects

J Lim; A C Hire; Y Quan; J S Kim; S R Xie; S Sinha; R S Kumar; D Popov; C Park; R J Hemley; Y K Vohra; J J Hamlin; R G Hennig; P J Hirschfeld; G R Stewart

doi:10.1038/s41467-022-35191-8

Creating superconductivity in WB₂ through pressure-induced metastable planar defects

Nat Commun. 2022 Dec 22;13(1):7901. doi: 10.1038/s41467-022-35191-8.

Authors

J Lim^#¹, A C Hire^#^{2

3}, Y Quan^{1

2

3}, J S Kim¹, S R Xie^{2

3}, S Sinha¹, R S Kumar⁴, D Popov⁵, C Park⁵, R J Hemley⁴, Y K Vohra⁶, J J Hamlin⁷, R G Hennig^{2

3}, P J Hirschfeld¹, G R Stewart¹

Affiliations

¹ Department of Physics, University of Florida, Gainesville, FL, 32611, USA.
² Department of Materials Science and Engineering, University of Florida, Gainesville, FL, 32611, USA.
³ Quantum Theory Project, University of Florida, Gainesville, FL, 32611, USA.
⁴ Department of Physics, Chemistry, and Earth and Environmental Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA.
⁵ HPCAT, X-ray Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA.
⁶ Department of Physics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
⁷ Department of Physics, University of Florida, Gainesville, FL, 32611, USA. jhamlin@ufl.edu.

^# Contributed equally.

Abstract

High-pressure electrical resistivity measurements reveal that the mechanical deformation of ultra-hard WB₂ during compression induces superconductivity above 50 GPa with a maximum superconducting critical temperature, T_cof 17 K at 91 GPa. Upon further compression up to 187 GPa, the T_cgradually 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 MgB₂ (hP3, space group 191, prototype AlB₂). Synchrotron x-ray diffraction measurements up to 145 GPa show that the ambient pressure hP12 structure (space group 194, prototype WB₂) 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.