We revealed that the superconducting transition temperature Tc of the multi-component superconductor Sr2RuO4 is enhanced to 3.3 K under in-plane uniaxial pressure that reduces the tetragonal crystal symmetry. This result suggests that new superconducting phases with a one-component order parameter are induced. We have also clarified the inplane pressure direction dependence of the emergence of this higher-Tc superconducting phase: pressure along the [100] direction is more favorable than pressure along the [110] direction. This result is probably closely related to the direct shortening of the in-plane Ru-O bond length along the pressure direction and the approach of the gamma Fermi surface to the van Hove singularity under the pressure parallel to the [100] direction.
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