Phase-sensitive order parameter symmetry test experiments utilizing Nd2-xCexCuO4-y/Nb zigzag junctions

TL;DR

This study uses zigzag Josephson junctions to determine the order parameter symmetry of Nd2-xCexCuO4-y, revealing a predominant d-wave symmetry at low temperatures, consistent across doping levels.

Contribution

It provides phase-sensitive experimental evidence for the d-wave symmetry in electron-doped cuprates using a novel zigzag junction approach.

Findings

Nd2-xCexCuO4-y exhibits d-wave symmetry at 4.2K.

No change to s-wave symmetry observed at 1.6K.

Results are consistent across doping levels.

Abstract

Phase-sensitive order parameter symmetry test experiments are presented on the electron-doped high-T_c cuprate Nd2-xCexCuO4-y. These experiments have been conducted using zigzag-shaped thin film Josephson structures, in which the Nd2-xCexCuO4-y is connected to the low-T_c superconductor Nb via a Au barrier layer. For the optimally doped as well as for the overdoped Nd2-xCexCuO4-y a clear predominant dx2-y2-wave behavior is observed at T=4.2K. Both compounds were also investigated at T=1.6K, presenting no indications for a change to a predominant s-wave symmetry with decreasing temperature.