Oxygen isotope effect on the in-plane penetration depth in underdoped La_{2-x}Sr_{x}CuO_{4} single crystals

TL;DR

This study investigates how oxygen isotope substitution affects the in-plane penetration depth in underdoped La_{2-x}Sr_{x}CuO_{4} crystals, revealing significant isotope effects linked to lattice vibrations and superconductivity.

Contribution

It provides precise measurements of the oxygen isotope effect on the penetration depth, highlighting the role of lattice vibrations in high-temperature superconductivity.

Findings

Oxygen isotope effect on b^{-2}(0) is approximately -10% and -8% for different doping levels.

The isotope effect mainly results from changes in the in-plane effective mass m_{ab}*.

Lattice vibrations are significant for high-temperature superconductivity.

Abstract

We report measurements of the oxygen isotope effect (OIE) on the in-plane penetration depth \lambda_{ab}(0) in underdoped La_{2-x}Sr_{x}CuO_{4} single crystals. A highly sensitive magnetic torque sensor with a resolution of \Delta \tau ~ 10^{-12} Nm was used for the magnetic measurements on microcrystals with a mass of ~ 10 microg. The OIE on \lambda_{ab}^{-2}(0) is found to be -10(2)% for x = 0.080 and -8(1)% for x = 0.086. It arises mainly from the oxygen mass dependence of the in-plane effective mass m_{ab}*. The present results suggest that lattice vibrations are important for the occurrence of high temperature superconductivity.