Results obtained from several tunneling experiments on the pairing symmetry in Sr2RuO4 are reported. A normal surface layer was found to be present on the ab face of single-crystalline Sr2RuO4 in the c-axis tunnel junctions. Measurements in the in-plane junctions, however, revealed features suggesting a suppressed, but non-zero superconducting gap and Andreev bound states (ABSs) associated only with an unconventional superconductor. Josephson coupling between a conventional s-wave superconductor and Sr2RuO4 has been used to probe the pairing symmetry in the latter, through both the selection rule and the phase sensitive experiments. All results indicate that Sr2RuO4 is unconventional, most likely spin-triplet superconductor. Finally, some recent studies of several newly-characterized ruthenates are reviewed.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Materials Science(all)
- Condensed Matter Physics