Dynamical Interplay between Coexisting Orders in the Electron-Doped Cuprate Superconductor Nd_{2-x}Ce_xCuO_4

TL;DR

This study investigates the dynamic interactions between superconducting and antiferromagnetic orders in Nd_{2-x}Ce_xCuO_{4+ extdelta} using pump-probe spectroscopy, revealing critical fluctuations and coupling effects near the transition temperatures.

Contribution

It provides new insights into the interplay of coexisting orders in electron-doped cuprates through time-resolved optical measurements.

Findings

Negative reflectivity change above T_c indicating critical fluctuations

Positive reflectivity change at T_c linked to superconductivity

Strong coupling suggesting repulsive interaction between orders

Abstract

We use coherent pump-probe spectroscopy to measure the photoinduced reflectivity \DeltaR, and complex dielectric function, {\delta}\in, of the electron-doped cuprate superconductor Nd_{2-x}Ce_xCuO_{4+\delta} at a value of x near optimal doping, as a function of time, temperature, and laser fluence. We observe the onset of a negative \DeltaR at T=85 K, above the superconducting transition temperature, T_c, of 23 K, that exhibits a form of scaling consistent with critical fluctuations in the time domain. A positive \Delta R onsets at T_c that we associate with superconducting order. We find that the two signals are strongly coupled below T_c, in a manner that suggests a repulsive interaction between superconductivity and antiferromagnetic correlations.