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arXiv · 2309.16917

Atomic-scale mechanism of enhanced electron-phonon coupling at the interface of MgB$_2$ thin film

Xiaowen Zhang·Tiequan Xu·Ruochen Shi·Bo Han·Fachen Liu·Zhetong Liu·Xiaoyue Gao·Jinlong Du·Yue Wang·Peng Gao
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Abstract

In this study, we explore the heterointerface of MgB$_2$ film on SiC substrate at atomic scale using electron microscopy and spectroscopy. We detect ~1 nm MgO between MgB$_2$ and SiC. Atomic-level electron energy loss spectra (EELS) show MgB$_2$-E2g mode splitting and softening near the MgB$_2$/MgO interface. Orbital-resolved core-level EELS link the phonon softening to in-plane boron-atom electron states' changes. Ab initio calculations confirm this softening enhances electron-phonon coupling at the interface. Our findings highlight interface engineering's potential for superconductivity enhancement.

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Xiaowen Zhang, Tiequan Xu, Ruochen Shi, Bo Han, Fachen Liu, Zhetong Liu, Xiaoyue Gao, Jinlong Du, Yue Wang, Peng Gao. 2023-09-29. Atomic-scale mechanism of enhanced electron-phonon coupling at the interface of MgB$_2$ thin film. https://arxiv.org/abs/2309.16917

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