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The superconducting electronic states of Nd 1.85 Ce 0.15 CuO 4Ϫ␦ ͑NCCO͒ are studied by applying the phasesensitive capability of tunneling spectroscopy. Unlike the YBa 2 Cu 3 O 7Ϫ␦ cases, the conductance spectra measured on ͑100͒-, ͑110͒and ͑001͒-oriented surfaces showed V-shaped gap structures, and no zero-bias conductance peaks were observed even around steps on the surfaces. The present results reject the possibility of d x 2 Ϫy 2-wave and d xy -wave symmetries for the pair potential in NCCO. The experimental spectra are well fitted to theoretical curves of anisotropic s-wave symmetry with a large smearing factor.

Sr2RuO4 is one of the most promising candidates of a topological superconductor with broken time-reversal symmetry, because a number of experiments have revealed evidences for a spin-triplet chiral p-wave superconductivity. In order to clarify the time-reversal symmetry of Sr2RuO4, we introduce a novel test that examines the invariance of the Josephson critical current under the inversion of both the current and magnetic fields, in contrast to the detection of a spontaneous magnetic field employed in past experiments. Analyses of the transport properties of the planar and corner Josephson junctions formed between Sr2RuO4 and Nb reveal the time-reversal invariant superconductivity, most probably helical p-wave, of Sr2RuO4. This state corresponds to a yet-to-be confirmed topologicalcrystallinesuperconductivity that can host two Majorana edge modes at the surface protected by crystalline mirror symmetry. arXiv:1907.03939v2 [cond-mat.supr-con]