Oxygen isotope effect on the superconductivity and stripe phase in La$_{1.6-x}$Nd$_{0.4}$Sr$_{x}$CuO$_4$

TL;DR

This study investigates how replacing oxygen isotopes affects superconductivity, stripe phases, and structural transitions in La-based cuprates, revealing that isotope substitution suppresses superconductivity and enhances stripe order.

Contribution

It provides new evidence that oxygen isotope substitution influences the competition between stripe phases and superconductivity in La-based cuprates.

Findings

Replacing $^{16}$O with $^{18}$O decreases T$_C$

Isotope substitution increases the structural transition temperature

Larger isotope effect observed in Nd-doped samples

Abstract

The oxygen isotope effect on the superconductivity, stripe phase and structure transition is systematically investigated in La$_{1.6-x}$Nd$_{0.4}$Sr$_{x}$CuO$_4$ with static stripe phase. Substitution of $^{16}$O by $^{18}$O leads to a decrease in superconducting transition temperature T$_C$, while enhances the temperature of the structural transition from low-temperature-orthorhombic (LTO) phase to low-temperature-tetragonal (LTT) phase. Compared to the Nd free sample, a larger isotope effect on $T_C$ is observed in La$_{1.6-x}$Nd$_{0.4}$Sr$_{x}$CuO$_4$. These results indicate that the distortion of CuO$_2$ plane suppresses the superconductivity, giving a direct evidence for the competing of stripe phase and superconductivity because the distortion of CuO$_2$ plane enhances the stripe phase.