2017 Fiscal Year Final Research Report
Electrochemical etching approarch to ultrathin films
| Project/Area Number |
16H05981
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| Research Category |
Grant-in-Aid for Young Scientists (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Thin film/Surface and interfacial physical properties
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2018-03-31
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| Keywords | 層状物質 / カルコゲナイド物質 / 超伝導 |
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| Outline of Final Research Achievements |
Electrochemical etching technique has been applied to layered materials in electric-double layer transistor. Exotic physical properties, absent in bulk form, are expected to emerge in ultrathin limit. A one of the typical examples is layered superconducting iron selenide (FeSe), with superconducting transition temperature (Tc) of 8 K in bulk. The monolayer-thick FeSe exhibits high-Tc at 65 K as discovered by spectroscopic measurements. In this work, we applied electrochemical etching to FeSe films to reveal superconducting critical parameters in high-Tc state in ultrathin limit. We found that the isotropic upper critical field (Hc2) in bulk FeSe is converted to highly anisotropy one in high-Tc state. Based on Ginzburg-Landau model, anisotropic Hc2 exhibits three-dimensional nature rather than two dimensional one, which indicates strong confinement of Cooper pair within FeSe sheet. We consider that this confinement effect stabilizes the high-Tc state of FeSe in monolayer-thick limit.
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| Free Research Field |
層状物質
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