2015 Fiscal Year Annual Research Report
Unconventional Superconductivity in semiconductor systems
| Project/Area Number |
25800197
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Kriener Markus 国立研究開発法人理化学研究所, 創発物性科学研究センター, 研究員 (60447919)
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Keywords | Topological Insulators / Topological SC / Semiconductors / Unconventional SC / polar semiconductors |
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| Outline of Annual Research Achievements |
This project was aimed for the fiscal years 2013 and 2014. It was extended last year by one year.
The main results and achievements are already summarized in last year's progress report. Since then two more papers were submitted which are now both accepted for publication. One is about a collaboration on the electron-doped topological insulator CuxBi2Se3 project where the possibly topological superconducting phase was probed by NMR. In this experiment, evidence for a spontaneously broken spin-rotation symmetry in the hexagonal plane of CuxBi2Se3 below the superconducting transition temperature was found. This supports the unconventional spin-triplet scenario of superconductivity discussed for this system. Moreover this is the first clear evidence for a broken spin-rotational symmetry in a superconducting system.
The second accepted publication is about the polar semiconductor GeTe, where two competing ferromagnetic phases were found upon Mn doping. One of these had not been identified before. Which of the two phases is realized depends on the heat treatment of a sample. A spinodal decomposition was identified to be the origin of these two distinct phases. Moreover it was found that samples can be switched between the two magnetic phases back and forth and hence this effect is demonstrating magnetic phase change memory functionality, i.e., a magnetic analog of the structural phase change memory function as it is utilized in, e.g., DVDs. This finding adds a new feature to the multifunctional system GeTe. A patent application on this effect is on the way.
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