Superconducting transport phenomena and the electron structures in semiconductor nanowires

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H05407
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Nanostructural physics
• Research Institution: The University of Tokyo
• Principal Investigator: Matsuo Sadashige 東京大学, 大学院工学系研究科(工学部), 助教 (90743980)
• Co-Investigator(Renkei-kenkyūsha): TARUCHA Seigo 東京大学, 大学院工学系研究科, 教授 (40302799)
• Research Collaborator: BABA Shoji ; TATENO Mizuki ; UEDA Kento ; SATO Yosuke ; TAKESHIGE Yuusuke ; KAMATA Hiroshi
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: マヨラナ粒子 / トポロジカル超伝導 / 半導体ナノ細線

Outline of Final Research Achievements

About junctions of superconductors and double InAs nanowires, we established the fabrication technique and demonstrated Cooper pair splitting in the junctions via quantum dots occasionally formed in the nanowires. Furthermore, we demonstrated Cooper pair splitting in the ballistic double nanowire junctions. We also fabricated the nice interface between NbTi and InAs quantum well and realized coexistence of superconductivity and spin-resolved quantum Hall effect. In the junctions, we observed conductance enhancement around zero bias voltage as a signature of equal-spin Andreev reflection. In addition, we found the half-integer quantized conductance plateaus in InAs quantum wire and in-plane fields makes the plateau conductance decrease, meaning the e-e interaction can be assigned as the origin instead of the spin-orbit interaction. We succeeded in gate control of supercurrent in Corbino-geometry Josephson junction and estimation of vortex size from the field dependence.

Free Research Field

メゾスコピック物理