Development of rare-earth based trivial- and topological-insulators toward innovative optical-devices

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05035
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied materials
• Research Institution: Fukuoka Institute of Technology
• Principal Investigator: Kitagawa Jiro 福岡工業大学, 工学部, 教授 (90346528)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 光誘起近藤効果 / 電気二重層トランジスタ / 近藤絶縁体 / 低消費電力光デバイス

Outline of Final Research Achievements

The purposes of this project are the assessment of universality of photoinduced Kondo effect, which has been proposed by us, and the materials research on Kondo insulators. We have proposed the devise based on the electric double layer transistor (EDLT). In the devise, a Ce or Yb based semiconductor is required, for which the metal organic decomposition method is employed. Ce-based thin films were synthesized, however, a compound containing Ce+3 ion could not be obtained. We have succeeded in obtaining YbMnO3 film and characterized the EDLT on YbMnO3. We have observed no electric-field-induced carriers in the devise. We additionally tried a carrier doping through a plasma processing. The nitriding of TiO2 films, following the reports of the other group, is not successful. In the materials research on Kondo insulators, we have tried the synthesize of samples with the ZrCuSiAs- and Sr2Mn3As2O2- types and with the carrier-doped Zintl phase. All samples did not form the desired phases.

Free Research Field

磁性・超伝導材料

Academic Significance and Societal Importance of the Research Achievements

光による磁気制御は、MO,MDなどで実用化されたが、光照射密度は記録時に106 W/cm2と極めて大きい。光誘起近藤効果の発現には、10 W/cm2もあれば十分であり、この普遍性が確認できれば、光磁気記録装置や光変調器などの省電力化が期待できる。また、トポロジカル近藤絶縁体が見つかれば、応用として、高周波デバイス、熱電変換素子、スピントロニクスデバイスなど極めて多くの例が挙げられている。さらに、トポロジカル相の光制御を用いれば、スピン流などの光変調が可能となり、トポロジカル絶縁体デバイスの高機能化が期待される。