Evidence for complex order parameter in La_{1.83}Sr_{0.17}CuO_4

TL;DR

This study provides evidence for a complex two-gap order parameter in La_{1.83}Sr_{0.17}CuO_4, revealing both d-wave and s-wave superconducting gaps through muon-spin rotation measurements.

Contribution

The paper demonstrates the presence of two distinct superconducting gaps with different symmetries in La_{1.83}Sr_{0.17}CuO_4, a novel finding in this material.

Findings

Identification of two superconducting gaps with different symmetries.

Quantitative values of the gaps at zero temperature.

Observation of an inflection point in the temperature dependence of b^-2.

Abstract

The in-plane magnetic field penetration depth (\lambda_{ab}) in single-crystal La_{1.83}Sr_{0.17}CuO_4 was investigated by means of the muon-spin rotation (\muSR) technique. The temperature dependence of \lambda^{-2}_{ab} has an inflection point around 10-15K, suggesting the presence of two superconducting gaps: a large gap (\Delta_1^d) with d-wave and a small gap (\Delta_2^s) with s-wave symmetry. The zero-temperature values of the gaps at \mu_0H=0.02T were found to be \Delta_1^d(0)=8.2(2)meV and \Delta_2^s(0)=1.57(8)meV.