2013 Fiscal Year Final Research Report
Study of superconductivity in bismuth-alloys by simultaneous measurement of transport and structural properties at high pressures and low temperatures
| Project/Area Number |
24740229
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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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 | Niigata University |
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Principal Investigator |
OHMURA AYAKO 新潟大学, 研究推進機構, 助教 (60425569)
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| Project Period (FY) |
2012-04-01 – 2014-03-31
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| Keywords | 高圧固体物性 / トポロジカル絶縁体 / 超伝導 |
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| Research Abstract |
This study reports pressure-induced superconducting transition in three-dimensional topological insulators investigated by the electrical resistivity measurement and the synchrotron radiation x-ray diffraction under pressure. Cu0.25Bi2(Te1-xSex)3 with concentration of x=0.01 and 0.1, which is the family of topological-superconductor candidate CuyBi2Se3, show the superconducting transitions at temperature of Tc~5K above 10 GPa. In x=0.01, the monoclinic high-pressure phase II appears at 10.9 GPa with increasing pressure. Pressure-induced superconducting transition in x=0.01, therefore, is attributed to the formation of HP-phase II. The highly bulk-insulating topological insulator Bi2Te2Se shows superconductivity at temperature of Tc~3 K above 8 GPa. At this pressure, temperature dependence of resistivity exhibits semiconducting behavior with high resistivity. Thus, in Bi2Te2Se, there is a possibility that the topological insulator phase makes the transition to the superconducting state.
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