Supercurrent through grain boundaries in the presence of strong correlations

TL;DR

This paper extends the Gutzwiller projection method to analyze how strong electronic correlations affect the critical current through grain boundaries in high-temperature cuprate superconductors, showing good agreement with experiments.

Contribution

It introduces a consistent approach to treat correlations below and above half-filling and applies it to grain boundary current analysis in cuprates.

Findings

Excellent agreement with experimental data for hole-doped systems.

Correlation effects significantly influence critical current across grain boundaries.

Comparison with weak-coupling methods highlights the importance of strong correlations.

Abstract

Strong correlations are known to severely reduce the mobility of charge carriers near half-filling and thus have an important influence on the current carrying properties of grain boundaries in the high-$T_c$ cuprates. In this work we present an extension of the Gutzwiller projection approach to treat electronic correlations below as well as above half-filling consistently. We apply this method to investigate the critical current through grain boundaries with a wide range of misalignment angles for electron- and hole-doped systems. For the latter excellent agreement with experimental data is found. We further provide a detailed comparison to an analogous weak-coupling evaluation.