08.06.2021; Kolloquium
Evidence for two-component superconductivity in Sr2RuO4 from ultrasound measurements
Abstract:
The unconventional superconductivity of Sr2RuO4 has remained a mystery for over 25 years, even though its normal metallic state is quite well understood. Reaching a consensus on the bulk order parameter symmetry has been primarily difficult due to the discrepancies that exist between several major experimental evidences [1]. We use resonant ultrasound spectroscopy to measure the entire symmetry-resolved elastic tensor of Sr2RuO4 through the superconducting transition. We observe a thermodynamic discontinuity in the shear elastic modulus c66, requiring that the superconducting order parameter is two-component [2]. We also find an anomalous increase in compressional sound attenuation immediately below Tc, in sharp disagreement with what is found in both conventional (s-wave) and high-Tc (d-wave) superconductors.
[1] A. P. Mackenzie et al., npj Quant. Mater. 2, 40 (2017)
[2] S. Ghosh et al., Nat. Phys. 17, 199–204 (2021)
Host: D. Peets
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