Evolution of a bosonic mode across the superconducting dome in the high-Tc cuprate Pr(2-x)Ce(x)CuO(4-{\delta})

TL;DR

This study investigates how bosonic excitations in electron-doped cuprate superconductor Pr(2-x)Ce(x)CuO(4-{ ho}) evolve across different doping levels, revealing their likely spin excitation origin and their disappearance above critical temperature and magnetic field.

Contribution

It provides detailed spectroscopic evidence of doping-dependent bosonic resonances and their association with spin excitations in Pr(2-x)Ce(x)CuO(4-{ ho}).

Findings

Bosonic excitations decrease in energy with increased doping.

These excitations vanish above the critical temperature and magnetic field.

Lattice vibrations are unlikely to be the pairing mechanism.

Abstract

We report a detailed spectroscopic study of the electron doped cuprate superconductor Pr(2-x)Ce(x)CuO(4-{\delta}) using point contact junctions for x=0.125(underdoped), x=0.15(optimally doped) and x=0.17(overdoped). From our conductance measurements we are able to identify bosonic resonances for each doping. These excitations disappear above the critical temperature, and above the critical magnetic field. We find that the energy of the bosonic excitations decreases with doping, which excludes lattice vibrations as the paring glue. We conclude that the bosonic mediator for these cuprates is more likely to be spin excitations.