Theory of tunneling conductance for normal metal/insulator/triplet superconductor junctions

TL;DR

This paper provides a theoretical analysis of tunneling conductance in normal metal/insulator/triplet superconductor junctions, highlighting how conductance spectra depend on junction orientation and pairing symmetry, aiding experimental identification of superconductor states.

Contribution

It introduces a theoretical framework for tunneling conductance spectra in triplet superconductor junctions, considering various pairing symmetries relevant to UPt3 and Sr2RuO4.

Findings

Conductance spectra are orientation-dependent.

Zero-bias conductance peaks or gap-like structures appear based on orientation.

Residual density of states influences conductance spectra in nonunitary states.

Abstract

Tunneling conductance spectra of normal metal/insulator/triplet superconductor junctions are investigated theoretically. As triplet paring states we select several types of symmetries that are promising candidates for the superconducting states in UPt$_{3}$ and in Sr$_{2}$RuO$_{4}$. The calculated conductance spectra are sensitive to the orientation of the junction which reflects the anisotropy of the pairing states. They show either zero-bias conductance peaks or gap-like structures depending on the orientation of the junctions. The existence of a residual density of states, peculiar to nonunitary states, is shown to have a significant influence on the properties of the conductance spectra. Present results serve as a guidefor the experimental determination of the symmetry of the pair potentials in UPt$_{3}$ and Sr$_{2}$RuO$_{4}$.