2020 Fiscal Year Annual Research Report
Application of the micro-fabrication technique to the study of nematicity and superconductivity
Publicly Offered Research
| Project Area | Physical Properties of Quantum Liquid Crystals |
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| Project/Area Number |
20H05164
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| Research Institution | Aoyama Gakuin University |
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Principal Investigator |
孫 悦 青山学院大学, 理工学部, 助教 (30824180)
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| Project Period (FY) |
2020-04-01 – 2022-03-31
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| Keywords | nematic phase / micro-fabrication / FeSe / superconductivity |
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| Outline of Annual Research Achievements |
Combined the micro-support equipment and the FIB pick-up technique, we have successfully fabricated a series of a c-axis lamella from the high-quality FeSe and FeTe0.6Se0.4 single crystals. With this lamella, we can put contacts along the c-axis, to directly measure the out-of-plane transport properties.The c-axis resistivity, current-voltage curve, critical current density, upper critical fields, and magnetoresistance with current along c axis were studied.
We also setted up a low temperature measurmental system with 9 T magnetic field, including a sample probe with rotator. With such system, we observed a in-plane 2-fold signal from the angle resolved magnetoresistance measurements, which supports the nexistence of nematic phase.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We successfully fabricated a c-axis lamella for the precise measurement with current along c axis. Such devices can be used to study the nematic phase.
We also setted up a measurement system with angle resolved magnetic field, which enables us to perform the measurements, such as the angle resolved magnetoresistance, needed for identify the nematic phase.
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| Strategy for Future Research Activity |
Firstly, we will continue the transport measurements of the fabricated a c-axis lamella from Fe(Te,Se) single crystals under higher field. We also plan to explore the FIB micro-fabrication technique to other materials such as the IBSs “122”, SrxBi2Se3, and PbTaSe2. Besides, based on the narrow bridges shown in Fig. 2, we can further reduce the size of the center part down to 100 nm, and try to make the Josephson junctions both in-plane and out-of-plane. We can also try to deposit Pt thin film on the bridge to make the normal metal-superconductor (NS) junctions. At the meantime, the tunneling spectroscopy (dI/dV) will also be applied to measure the superconducting gap size. Together with the rotating magnetic field, evidence for the nematicity in the SC state is hopefully to be revealed.
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