Direct evidence for the absence of coupling between shear strain and superconductivity in Sr2RuO4

Giordano Mattoni; Thomas Johnson; Atsutoshi Ikeda; Shubhankar Paul; Jake Bobowski; Manfred Sigrist; Yoshiteru Maeno

doi:10.1038/s41467-025-67307-1

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arXiv · 2509.10215

Direct evidence for the absence of coupling between shear strain and superconductivity in Sr2RuO4

Giordano Mattoni·Thomas Johnson·Atsutoshi Ikeda·Shubhankar Paul·Jake Bobowski·Manfred Sigrist·Yoshiteru Maeno

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Abstract

The superconducting symmetry of Sr2RuO4 has been intensely debated for many years. A crucial controversy recently emerged between shear-mode ultrasound experiments, which suggest a two-component order parameter, and some uniaxial pressure experiments that suggest a one-component order parameter. To resolve this controversy, we use a new approach to directly apply three different kinds of shear strain to single crystals of Sr2RuO4 and investigate the coupling to superconductivity. After characterising the strain by optical imaging, we observe variations of the transition temperature Tc smaller than 10mK/% as measured by low-frequency magnetic susceptibility, indicating that shear strain has little to no coupling to superconductivity. Our results are consistent with a one-component order parameter model, but such a model cannot consistently explain other experimental evidence such as time-reversal symmetry breaking, superconducting domains, and horizontal line nodes, thus calling for alternative interpretations.

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Giordano Mattoni, Thomas Johnson, Atsutoshi Ikeda, Shubhankar Paul, Jake Bobowski, Manfred Sigrist, Yoshiteru Maeno. 2025-09-12. Direct evidence for the absence of coupling between shear strain and superconductivity in Sr2RuO4. https://doi.org/10.1038/s41467-025-67307-1

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