Enhancement of superconducting fluctuation under the coexistence of a competing pseudogap state in Bi2Sr2-xRxCuOy

TL;DR

This study investigates how the pseudogap state influences superconducting fluctuations in Bi2Sr2-xRxCuOy, revealing that pseudogap suppresses Tc but enhances fluctuations, with distinct onset temperatures for superconductivity and pseudogap phenomena.

Contribution

It provides new experimental insights into the relationship between pseudogap states and superconducting fluctuations in cuprate superconductors.

Findings

Pseudogap suppresses the critical temperature Tc.

Superconducting fluctuation onset temperature Tonset is distinct from T*.

Pseudogap enhances superconducting fluctuations without significantly affecting Tonset.

Abstract

The onset temperature of superconducting fluctuation Tonset of Bi2Sr2-xRxCuOy (R=La and Eu) was studied by measuring the Nernst effect. We found that Tonset has a x and R dependence that is quite different from both the pseudogap temperature T* and the critical temperature Tc. Our results support the picture that the incoherent superconductivity, which has been observed below Tonset, is qualitatively different from the pseudogap phenomenon that is characterized by T*. The experimentally obtained phase diagram indicates that the pseudogap state suppresses Tc and enhances superconducting fluctuation while having only small influence on Tonset.