Nernst effect in the electron-doped cuprate superconductor La2-xCexCuO4

TL;DR

This study investigates the Nernst effect in La2-xCexCuO4 films across various doping levels, revealing how superconducting fluctuations and magnetic order influence superconductivity's onset and characteristics.

Contribution

It provides a systematic analysis of the Nernst effect and superconducting fluctuations in electron-doped cuprates, linking magnetic order and doping to superconducting properties.

Findings

HC2* tracks the superconducting dome with doping.

Superconducting fluctuation onset temperature decreases with doping.

Superconducting gap closely follows HC2* measurements.

Abstract

We report a systematic study of the Nernst effect in films of the electron doped cuprate superconductor La2-xCexCuO4 (LCCO) as a function of temperature and magnetic field (up to 14 T) over a range of doping from underdoped (x=0.08) to overdoped (x=0.16). We have determined the characteristic field scale HC2* of superconducting fluctuation which is found to track the dome-like dependence of superconductivity (TC). The fall of HC2* and TC with underdoping is most likely due to the onset of long range anti-ferromagnetic order. We also report the temperature onset, Tonset, of superconducting fluctuations above TC. For optimally doped x=0.11 Tonset (39 K) is high compared to TC (26 K). For higher doping Tonset decreases and tends to zero along with the critical temperature at the end of the superconducting dome. The superconducting gap closely tracks HC2* measured from the temperature and field dependent Nernst signal.