Nernst Effect of stripe ordering La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$

TL;DR

This study examines the Nernst effect in stripe-ordered La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$ and finds anomalies near charge stripe order onset, with implications for understanding Nernst responses in hole-doped cuprates.

Contribution

It provides detailed measurements of the Nernst effect across different doping levels, highlighting anomalies associated with stripe order and comparing these with superconducting counterparts.

Findings

Kink-like anomalies near stripe order onset in certain doping levels.

Weak differences in Nernst response between stripe-ordered and superconducting samples.

Challenges existing theories on Nernst effect origins in cuprates.

Abstract

We investigate the transport properties of La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$ ($x=0.04$, 0.08, 0.125, 0.15, 0.2) with a special focus on the Nernst effect in the normal state. Various anomalous features are present in the data. For $x=0.125$ and 0.15 a kink-like anomaly is present in the vicinity of the onset of charge stripe order in the LTT phase, suggestive of enhanced positive quasiparticle Nernst response in the stripe ordered phase. At higher temperature, all doping levels except $x=0.2$ exhibit a further kink anomaly in the LTO phase which cannot unambiguously be related to stripe order. Moreover, a direct comparison between the Nernst coefficients of stripe ordering La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$ and superconducting La$_{2-x}$Sr$_x$CuO$_4$ at the doping levels $x=0.125$ and $x=0.15$ reveals only weak differences. Our findings make high demands on any scenario interpreting the Nernst response in hole-doped cuprates.