Macroscopic evidence for quantum criticality and field-induced quantum fluctuations in cuprate superconductors

TL;DR

This study provides macroscopic evidence that cuprate superconductors exhibit quantum criticality and field-induced quantum fluctuations, indicated by suppressed irreversibility fields across various doping levels and structures.

Contribution

It demonstrates the presence of quantum fluctuations in cuprates through macroscopic measurements, highlighting their proximity to quantum critical points.

Findings

Suppression of zero-temperature in-plane magnetic irreversibility field

Evidence of strong quantum fluctuations in cuprates

Universality across different cuprate types

Abstract

We present macroscopic experimental evidence for field-induced microscopic quantum fluctuations in different hole- and electron-type cuprate superconductors with varying doping levels and numbers of CuO$_2$ layers per unit cell. The significant suppression of the zero-temperature in-plane magnetic irreversibility field relative to the paramagnetic field in all cuprate superconductors suggests strong quantum fluctuations due to the proximity of the cuprates to quantum criticality.