2016 Fiscal Year Final Research Report
Charge Kondo effect in valence-skipper-doped superconductor
| Project/Area Number |
26610102
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Condensed matter physics II
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | 超伝導 / 原子価スキップ |
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| Outline of Final Research Achievements |
We report a 125Te-NMR study of single-crystalline Pb1-xTlxTe, revealing an increase in the average density of states (DOS) coupled to a strong spatial variation in the local DOS surrounding each Tl dopant. For the superconducting composition, the nuclear spin relaxation rate for Te ions that are close to the Tl dopants is unexpectedly enhanced in the normal state below a characteristic temperature of 10 K. This temperature coincides exactly with the temperature below which the normal state resistivity experiences an upturn. These observations provide microscopic evidence for dynamical charge fluctuations, and is consistent with expectations for charge Kondo behavior associated with the Tl dopant ions. In contrast, such anomalies were not detected in the non-superconducting samples, suggesting a connection between dynamical valence fluctuations and the occurrence of superconductivity in Pb1-xTlxTe.
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| Free Research Field |
物性物理
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