Commensurate spin dynamics in the superconducting state of an electron-doped cuprate superconductor

TL;DR

This study reveals that electron-doped Nd2-xCexCuO4 exhibits commensurate spin fluctuations and a temperature-dependent spin gap in the superconducting state, contrasting with hole-doped cuprates' incommensurate fluctuations and pseudogap behavior.

Contribution

It provides new insights into the spin dynamics of electron-doped cuprates, highlighting differences from hole-doped counterparts and advancing understanding of their superconducting mechanisms.

Findings

Electron-doped cuprates show commensurate magnetic fluctuations.

A spin gap opens in the superconducting state, increasing as temperature decreases.

Contrasts with the T-independent pseudogap in hole-doped cuprates.

Abstract

We report neutron scattering studies on single crystals of the electron-doped (n-type) superconducting cuprate Nd2-xCexCuO4 (x=0.15) with Tc = 18 K and 25 K. Unlike the hole-doped (p-type) superconducting cuprates where incommensurate magnetic fluctuations commonly exist, the n-type cuprate shows commensurate magnetic fluctuations at the tetragonal (1/2 1/2 0) reciprocal points both in the superconducting and in the normal state. A spin gap opens up when the n-type cuprate becomes superconducting, as in the optimally doped p-type La2-xSrxCuO4. The gap energy, however, increases gradually up to about 4 meV as T decreases from Tc to 2 K, which contrasts with the spin pseudogap behavior with a T-independent gap energy in the superconducting state of p-type cuprates.