Essential Differences between $ab$ and $c$ Axis Tunneling and Zero Bias Conductance in the Cuprates

TL;DR

This paper investigates the tunneling characteristics in cuprate superconductors, revealing that anisotropic s-wave gaps mimic d-wave features and that c-axis conductance asymmetries arise from interlayer band splitting.

Contribution

It demonstrates that anisotropic s-wave gaps can produce d-wave-like tunneling features and explains c-axis conductance asymmetries through finite band splitting effects.

Findings

Anisotropic s-wave gaps exhibit d-wave-like conductance features.

Zero bias conductance asymmetry is linked to interlayer hopping.

Band splitting influences tunneling characteristics along the c-axis.

Abstract

The peculiarities in tunneling characteristics have been studied in the light of the controversy between s-wave and d-wave character of High $T_c$ superconductivity. We show that anisotropic s-wave gap has the same low voltage power law conductance and two peak structure in the density of states as d-wave superconductors. The asymmetric tunneling conductance and zero bias conductance for the c-axis tunneling is shown to occur because of finite band splitting coming from the interlayer hopping parameter.