arXiv subjects

Qingyu Hai

Publications and source records attributed to Qingyu Hai.

5 recordsLinked to original sources

arXiv2026

Optically Activated Superconductivity in MgB2 via Electroluminescent GaP Inhomogeneous Phase

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.

cond-mat.supr-con↗

arXiv2025

Luminescence-Induced Tunable Superconductivity in BSCCO via GaP Quantum Dots

The enhancement of superconducting properties in high-temperature copper-oxide superconductor B(P)SCCO remains a hot research topic in the field of superconducting materials. Building on previous research, here we introduce GaP quantum dots as an heterophase into the B(P)SCCO superconductor, aiming to enhance its superconductivity through the luminescent properties of GaP quantum dots. The experimental results demonstrate that the introduction of GaP quantum dots into B(P)SCCO generates significant tunable superconducting effects, leading to enhanced critical transition temperature (Tc), critical current density (Jc), and Meissner field (Hc) of B(P)SCCO with increasing luminescent intensity of the GaP quantum dots. The enhancement effect induced by GaP quantum dots exhibits a positive correlation with luminescent intensity, meaning samples with the addition of GaP quantum dots exhibiting higher luminescent intensity show elevated Tc, Jc, and Hc values. Unlike impurity effects, a distinct critical concentration dependency is observed. Notably, this GaP quantum dot modification strategy is not only effective in conventional superconductors but also applicable to high-temperature oxide superconductors.

cond-mat.supr-con↗

arXiv2023

Green light GaN p-n junction luminescent particles enhance the superconducting properties of B(P)SCCO Smart Meta-Superconductors (SMSCs)

Superconducting materials exhibit unique physical properties and hold great scientific value and vast industrial application prospects. However, due to limitations such as critical temperature (TC) and critical current density (JC), the large-scale application of superconducting materials remains challenging. Chemical doping has been a commonly used method to enhance the superconductivity of B(P)SCCO. However, satisfactory enhancement results have been difficult to achieve. In this study, we introduced green light GaN p-n junction particles as inhomogeneous phases into B(P)SCCO polycrystalline particles to form a smart meta-superconductors (SMSCs) structure. Based on the electroluminescence properties of the p-n junction, the Cooper pairs were stimulated and strengthened to enhance the superconductivity of B(P)SCCO. Experimental results demonstrate that the introduction of inhomogeneous phases can indeed enhance the critical temperature TC, critical current density JC, and complete diamagnetism (Meissner effect) of B(P)SCCO superconductors. Moreover, When the particle size of raw material of B(P)SCCO is reduced from 30μm to 5μm, the grain size of the sintered samples also decreases, and the optimal doping concentration of the inhomogeneous phases increases from 0.15 wt.% to 0.2 wt.%, further improving the enhancement of superconductivity.

cond-mat.supr-con↗

arXiv2023

Green-light p-n Junction Particle Inhomogeneous Phase Enhancement of MgB2 Smart Meta-Superconductor

Improving the critical temperature (TC), critical magnetic field (HC), and critical current (JC) of superconducting materials has always been one of the most significant challenges in the field of superconductivity, but progress has been slow over the years. Based on the concept of injecting energy to enhance electron pairing states, in this study, we have employed a solid-state sintering method to fabricate a series of smart meta-superconductors (SMSCs) consisting of p-n junction nanostructures with a wavelength of 550 nm, doped within an MgB2 matrix. Experimental results demonstrate that compared to pure MgB2 samples, the critical transition temperature (TC) has increased by 1.2 K, the critical current (JC) has increased by 52.8%, and the Meissner effect (HC) shows significant improvement in its diamagnetic properties. This phenomenon of enhanced superconducting performance can be explained by the coupling between superconducting electrons and evanescent waves.

cond-mat.supr-con↗

arXiv2022

An improved smart meta-superconductor MgB2

Increasing and improving the critical transition temperature (Tc), current density (Jc) and Meissner effect (Hc) of conventional superconductors are the most important problems in superconductivity research, but progress has been slow for many years. In this study, by introducing the p-n junction electroluminescent inhomogeneous phase with red wavelength to realize energy injection, we found the improved property of smart meta-superconductors MgB2, the critical transition temperature Tc increases by 0.8K, the current density Jc increases by 37%, and the diamagnetism of Meissner effect Hc also significantly improved, compared with pure MgB2. Compared with previous yttrium oxide inhomogeneous phase, p-n junction has higher luminescence intensity, longer stable life and simpler external field requirements. The coupling between superconducting electrons and surface plasmon polaritons may be explain this phenomenon. The realization of smart meta-superconductor by this electroluminescent inhomogeneous phase provides a new way to improve the performance of superconductors.

cond-mat.supr-con↗