Optically Activated Superconductivity in MgB2 via Electroluminescent GaP Inhomogeneous Phase

TL;DR

This study demonstrates that incorporating electroluminescent GaP phases into MgB2 enhances its superconducting properties by increasing electron-phonon coupling and flux pinning through optically activated mechanisms, without chemical modification.

Contribution

It introduces a novel method of tuning MgB2 superconductivity using in situ electroluminescent phases to activate light-phonon-electron interactions and improve performance.

Findings

Superconducting transition temperature Tc increased by ~1.4 K.

Critical current density Jc improved by ~69%.

Irreversibility field Hirr increased by ~31.5%.

Abstract

Experimental results demonstrate a viable strategy for tuning the superconducting properties of MgB2 through the incorporation of an electroluminescent inhomogeneous phase, revealing an interfacial light-phonon-electron synergistic mechanism that enhances superconductivity in conventional phonon-mediated systems. By introducing GaP electroluminescent inhomogeneous phases into MgB2 and activating their emission in situ through the application of a bias current during measurements, it is experimentally observed that the localized optical field and electromagnetic near field generated at the interface can effectively couple with the E2g phonon mode of the Mg-B layers, thereby significantly enhancing the electron-phonon interaction. As the emission intensity of the inhomogeneous phase increases, the interface light-field-driven mechanism markedly enhances the electron-phonon coupling constant lambda and leads to a gradual increase in the superconducting transition temperature Tc (with a maximum enhancement of approximately 1.4 K), enabling a tunable enhancement of the superconducting pairing channel in MgB2 without altering its primary chemical composition. In addition, the nanoscale dispersed distribution of the GaP inhomogeneous phase is expected to induce fine-scale defects that act as effective pinning centers and promote densification, resulting in an increase of the critical current density by approximately 69% at 20 K in the self-field and an enhancement of Hirr by about 31.5%. These results indicate that the electroluminescent inhomogeneous phase can synergistically enhance the superconducting performance of MgB2 through two mechanisms: "in situ near-field-enhanced pairing" and "structural pinning-assisted flux optimization", thereby providing a new design strategy for constructing superconducting material systems that can be activated by internal optical fields.