Mechanism of the High-Tc superconductivity in iron chalcogenide ultrathin films

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K13354
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Thin film/Surface and interfacial physical properties
• Research Institution: Tohoku University
• Principal Investigator: Shiogai Junichi 東北大学, 金属材料研究所, 助教 (30734066)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 電気二重層トランジスタ / 鉄系超伝導 / 層状物質

Outline of Final Research Achievements

Layered superconductor FeSe exhibits superconducting transition temperature (Tc) at 8 K in bulk form. Recent spectroscopic measurements have revealed that Tc is significantly increased to 60 K in single monolayer form. However, ex-situ electrical transport properties has not clearly addressed so far possibly due to degradation in air. In this study, we fabricated electric-double-layer transistors based on FeSe thick films and established the method to etch the FeSe film down to monolayer using electrochemical reaction. This electrochemical etching method allows to investigate dependence of superconducting properties on film thickness, oxide substrates, and electric field. From systematic electrical transport measurements in FeSe electric-double-layer transistors, we found that the charge balance in a specific band structure plays an important role to induce the high temperature superconductivity.

Free Research Field

薄膜工学