Resolving the order parameter of High-T$_{c}$ Superconductors through quantum pumping spectroscopy

TL;DR

This paper uses quantum pumping spectroscopy in a normal metal-superconductor setup to distinguish among different possible order parameters of high-temperature superconductors, providing a new experimental approach.

Contribution

It introduces a method to differentiate various high-Tc superconductor order parameters using quantum pumping spectroscopy.

Findings

Pumped current varies distinctly with different order parameters.

Heat and noise measurements help identify the superconductor's pairing symmetry.

The method effectively distinguishes s-wave, d-wave, and mixed order parameters.

Abstract

The order parameter of High-T$_{c}$ superconductors through a series of experiments has been quite conclusively demonstrated to not be of the normal $s-wave$ type. It is either a pure $d_{x^{2}-y^{2}}$-wave type or a mixture of a $d_{x^{2}-y^{2}}-wave$ with a small imaginary $s-wave$ or $d_{xy}-wave$ component. In this work a distinction is brought out among the four types, i.e., $s- wave$, $d_{x^{2}-y^{2}}- wave$, $d_{x^{2}-y^{2}}+is - wave$ and $d_{x^{2}-y^{2}}+id_{xy}- wave$ types with the help of quantum pumping spectroscopy. This involves a normal metal double barrier structure in contact with a High-T$_{c}$ superconductor. The pumped current, heat and noise show different characteristics with change in order parameter revealing quite easily the differences among these.