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arXiv · 1706.05790

Electronic structure and nematic phase transition in superconducting multi-layer FeSe films grown by pulsed laser deposition method

Bing Shen·Zhongpei Feng·Jianwei Huang·Yong Hu·Qiang Gao·Cong Li·Yu Xu·Guodong Liu·Li Yu·Lin Zhao·Kui Jin·X. J. Zhou
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Abstract

We report comprehensive angle-resolved photoemission investigations on the electronic structure of single crystal multiple-layer FeSe films grown on CaF2 substrate by pulsed laser deposition (PLD) method. Measurements on FeSe/CaF2 samples with different superconducting transition temperatures Tc of 4 K, 9 K and 14 K reveal electronic difference in their Fermi surface and band structure. Indication of the nematic phase transition is observed from temperature-dependent measurements of these samples; the nematic transition temperature is 140-160 K, much higher than 90 K for the bulk FeSe. Potassium deposition is applied onto the surface of these samples; the nematic phase is suppressed by potassium deposition which introduces electrons to these FeSe films and causes a pronounced electronic structure change. We compared and discussed the electronic structure and superconductivity of the FeSe/CaF2 films by PLD method with the FeSe/SrTiO3 films by molecular beam epitaxy (MBE) method and bulk FeSe. The PLD-grown multilayer FeSe/CaF2 is more hole-doped than that in MBE-grown multiple-layer FeSe films. Our results on FeSe/CaF2 films by PLD method establish a link between bulk FeSe single crystal and FeSe/SrTiO3 films by MBE method, and provide important information to understand superconductivity in FeSe-related systems.

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Bing Shen, Zhongpei Feng, Jianwei Huang, Yong Hu, Qiang Gao, Cong Li, Yu Xu, Guodong Liu, Li Yu, Lin Zhao, Kui Jin, X. J. Zhou. 2017-06-19. Electronic structure and nematic phase transition in superconducting multi-layer FeSe films grown by pulsed laser deposition method. https://doi.org/10.1088/1674-1056%2F26%2F7%2F077402

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