RESUMEN
We report unexpected phenomena observed on the Sr2RuO4-Ru eutectic phase featuring Ru islands embedded in a bulk crystal of the chiral p-wave superconductor Sr2RuO4. It was found that the Sr2RuO4/Ru interface is atomically sharp, terminated uniformly by a Sr/O layer. Surprisingly, the proximity-induced p-wave superconducting energy gap predicted by theory was not detected inside Ru islands. Our results suggest that the previously observed enhancement of superconductivity in this eutectic phase occurs away from rather than near the Sr2RuO4/Ru interface, where dislocations and phonon hardening were found.
RESUMEN
Superconductors with a chiral p-wave pairing are of great interest because they could support Majorana modes that could enable the development of topological quantum computing technologies that are robust against decoherence. Sr2RuO4 is widely believed to be a chiral p-wave superconductor. Yet, the mechanism by which superconductivity emerges in this, and indeed most other unconventional superconductors, remains unclear. Here we show that the local superconducting transition temperature in the vicinity of lattice dislocations in Sr2RuO4 can be up to twice that of its bulk. This is all the more surprising for the fact that disorder is known to easily quench superconductivity in this material. With the help of a phenomenological theory that takes into account the crystalline symmetry near a dislocation and the pairing symmetry of Sr2RuO4, we predict that a similar enhancement should emerge as a consequence of symmetry reduction in any superconductor with a two-component order parameter.