The Phase Diagram in Electron-Doped LCCO

TL;DR

This paper investigates the phase boundary between superconductivity and static magnetic order in electron-doped cuprate La2-xCexCuO4-d, revealing a sharp transition and suggesting greater symmetry between electron- and hole-doped cuprates.

Contribution

It provides new experimental evidence of a sharp phase boundary and the relationship between magnetism and superconductivity in electron-doped cuprates.

Findings

Static magnetism disappears near the onset of superconductivity.

Small doping or depth changes switch the material from superconducting to magnetic.

Results suggest higher symmetry between electron- and hole-doped cuprates.

Abstract

Superconductors are a striking example of a quantum phenomenon in which electrons move coherently over macroscopic distances without scattering. The high-temperature superconducting oxides(cuprates) are the most studied class of superconductors, composed of two-dimensional CuO2 planes separated by other layers which control the electron concentration in the planes. A key unresolved issue in cuprates is the relationship between superconductivity and magnetism. In this paper, we report a sharp phase boundary of static three-dimensional magnetic order in the electron-doped superconductor La2-xCexCuO4-d where small changes in doping or depth from the surface switch the material from superconducting to magnetic. Using low-energy spin polarized muons, we find static magnetism disappears close to where superconductivity begins and well below the doping where dramatic changes in the transport properties are reported. These results indicate a higher degree of symmetry between the electron and hole-doped cuprates than previously thought.