Emergence of superconductivity in the cuprates via a universal percolation process.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30337539.
- Also identified by DOI 10.1038/s41467-018-06707-y and PMC identifier 6193991.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
A pivotal step toward understanding unconventional superconductors would be to decipher how superconductivity emerges from the unusual normal state. In the cuprates, traces of superconducting pairing appear above the macroscopic transition temperature T<sub>c</sub>, yet extensive investigation has led to disparate conclusions. The main difficulty has been to separate superconducting contributions from complex normal-state behaviour. Here we avoid this problem by measuring nonlinear conductivity, an observable that is zero in the normal state. We uncover for several representative cuprates that the nonlinear conductivity vanishes exponentially above T<sub>c</sub>, both with temperature and magnetic field, and exhibits temperature-scaling characterized by a universal scale Ξ<sub>0</sub>. Attempts to model the response with standard Ginzburg-Landau theory are systematically unsuccessful. Instead, our findings are captured by a simple percolation model that also explains other properties of the cuprates. We thus resolve a long-standing conundrum by showing that the superconducting precursor in the cuprates is strongly affected by intrinsic inhomogeneity.