Atomic-scale mechanism of enhanced electron-phonon coupling at the interface of MgB₂ thin film

2023/09/29 by Zhang, Xiaowen, Xu, Tiequan, Shi, Ruochen +7
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Superconductivity (cond-mat.supr-con)

paper · doi:10.48550/arxiv.2309.16917

Abstract

In this study, we explore the heterointerface of MgB₂ film on SiC substrate at atomic scale using electron microscopy and spectroscopy. We detect ~1 nm MgO between MgB₂ and SiC. Atomic-level electron energy loss spectra (EELS) show MgB₂-E2g mode splitting and softening near the MgB₂/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.

Related

• Quantum geometry and critical temperature enhancement in MgB₂ superconductivity
• Ultra-thin Epitaxial MgB2 on SiC: Substrate Surface Polarity Dependent Properties
• Superconducting gap and electron-phonon interaction in MgB₂ thin film studied by point contacts
• Evidence of strong electron-phonon interaction in superconducting MgB₂ from electron tunneling
• Selective electron-phonon coupling strength from nonequilibrium optical spectroscopy: The case of MgB₂