Proposal for identifying possible even-parity superconducting states in Sr_{2}RuO_{4} using planar tunneling spectroscopy

Abstract

After more than 25 years of research, three even-parity superconducting states—the d+id-wave, d+ig-wave, and s+id-wave states—have emerged as leading candidates for the superconducting states of Sr_{2}RuO_{4}. In the present work, we propose a tunneling spectroscopy experiment for distinguishing among these three superconducting states. The key component of our proposal is that we examine the conductance spectra of normal-metal/Sr_{2}RuO_{4} junctions with various angles between the junction interface and the crystal axis of the Sr_{2}RuO_{4}. The angle dependence of the conductance spectra shows a unique pattern in each superconducting state, which can function as a fingerprint for verifying the pairing symmetry of Sr_{2}RuO_{4}.