Theoretical investigation of the four-layered self-doped high-T$_c$ superconductors: evidence of pair tunneling effect

TL;DR

This paper theoretically investigates four-layered self-doped high-Tc superconductors using a $t-J$ model, highlighting the significance of pair tunneling and explaining electron-hole asymmetry consistent with recent experiments.

Contribution

It introduces a four-layered self-doped $t-J$ model with pair tunneling, revealing the importance of pair tunneling in multi-layered high-Tc superconductors.

Findings

Superconducting gap for electron-doped layers is nearly twice that of hole-doped layers.

Results align with recent ARPES experiments on four-layered materials.

Pair tunneling significantly influences superconductivity in layered materials.

Abstract

Based on a four-layered self-doped $t-J$ type model and the slave-boson mean-field approach, we study theoretically the superconductivity in the electron-doped and hole-doped layers. The neighbor layers are coupled through both the single electron interlayer hopping and pair tunneling effect. The superconducting gap magnitude for the electron-doped band is nearly twice of that of the hole-doped one, which contrasts to our previous understanding of the electron-hole asymmetry in high-T$_c$ superconductors but consistent with recent angle-resolved-photoemission-spectroscopy experiments in four-layered materials Ba$_2$Ca$_3$Cu$_4$O$_8$F$_2$. Our results propose that the pair tunneling effect is important to examine the multi-layered superconducting materials.