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arXiv · 1608.00886

Correlation of Fe-based Superconductivity and Electron-Phonon Coupling in an FeAs/Oxide Heterostructure

Seokhwan Choi·Steven Johnston·Won-Jun Jang·Klaus Koepernik·Ken Nakatsukasa·Jong Mok Ok·Hyun-Jung Lee·Hyun Woo Choi·Alex Taekyung Lee·Alireza Akbari·Yannis K. Semertzidis·Yunkyu Bang·Jun Sung Kim·Jhinhwan Lee
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Abstract

Interfacial phonons between iron-based superconductors (FeSCs) and perovskite substrates have received considerable attention due to the possibility of enhancing preexisting superconductivity. Using scanning tunneling spectroscopy, we studied the correlation between superconductivity and e-ph interaction with interfacial-phonons in an iron-based superconductor Sr$_2$VO$_3$FeAs ($T_c \approx$ 33 K) made of alternating FeSC and oxide layers. The quasiparticle interference measurement over regions with systematically different average superconducting gaps due to the e-ph coupling locally modulated by O vacancies in VO$_2$ layer, and supporting self-consistent momentum-dependent Eliashberg calculations provide a unique real-space evidence of the forward-scattering interfacial phonon contribution to the total superconducting pairing.

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Seokhwan Choi, Steven Johnston, Won-Jun Jang, Klaus Koepernik, Ken Nakatsukasa, Jong Mok Ok, Hyun-Jung Lee, Hyun Woo Choi, Alex Taekyung Lee, Alireza Akbari, Yannis K. Semertzidis, Yunkyu Bang, Jun Sung Kim, Jhinhwan Lee. 2017-08-06. Correlation of Fe-based Superconductivity and Electron-Phonon Coupling in an FeAs/Oxide Heterostructure. https://doi.org/10.1103/physrevlett.119.107003

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