2001 Fiscal Year Final Research Report Summary
Studies of Symmetry of Order parameter of non-BCS superconductors by low temperature scanning tunneling microscopy and spectroscopy
| Project/Area Number |
11304021
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NISHIDA Nobuhiko Tokyo Institute of Technology, Professor, 大学院・理工学研究科, 教授 (50126140)
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| Co-Investigator(Kenkyū-buntansha) |
MSTSUMOTO Masashige Shizuoka University, Research Associate, 理学部, 助手 (20281058)
SAKATA Hideaki Tokyo Science University, Associate Professor, 理学部, 助教授 (30215636)
KANEKO Shin-ichi Tokyo Institute of Technology, Research Associate, 大学院・理工学研究科, 助手 (40301171)
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| Project Period (FY) |
1999 – 2001
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| Keywords | low temperature scanning tunneling spectroscopy and microscopy / high temperature superconductors / heavy fermion superconductors / superconducting vortex lattice / Bi_2Sr_2CaCu_2O_x / YNi_2B_2C / CeRu_2 / MgB_2 / quasi-particle density of states |
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| Research Abstract |
We have developed low temperature scanning tunneling microscope (LT-STM) with which we are able to perform scanning tunneling spectroscopy (STS) with energy resolution better than 10 μeV with an atomic spatial resolution below 1K in high magnetic fields up to 12 T. At 0.45K the precise STS/STM measurements were able to be performed. Combining our developed STM probe with 3He-4He dilution refrigerator, we are now ready for STS/STM in the temperature region of 0.1K. By using thus developed STS apparatus, we have made STS studies of possible candidates of non-BCS superconductors such as Bi_2Sr_2CaCu_2O_x, YNi_2B_2C, CeRu_2, UPd_2Al_3, CeCoIn_5, Sr_2RuO_4 and MgB_2. In Bi_2Sr_2CaCu_2O_x, YNi_2B_2C, CeRu_2 we have succeeded in observing vortices. The orbital symmetries of Cooper pairing of the superconductors have been studied by LT-STS. In polycrystalline MgB_2 STS measurements were performed from grain to grain and MgB_2 have been found to be a superconductor with 2 energy gaps which can be interpreted in terms of 2-band superconductor. We have indicated that LT-STS/STM is quite a powerful method for superconductivity studies.
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