| Project/Area Number |
22K13989
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Tu Ngoc Han 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, 特別研究員 (00862327)
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| Project Period (FY) |
2022-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2023: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2022: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | Topological insulators / Graphene / van der Waals / helical edge states / topological insulator / Majorana fermion / graphene / heterostructure |
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| Outline of Research at the Start |
We realize a new 2D-TI in a stacking structure of graphene and 3D-TI. The helical edge states in the proposed structure locate along the physical edges of the sample, which readily forms contacts with other materials, providing a platform for using this 2D-TI in future applications. Using the observed helical edge states, we investigate the Majorana bound state (MBS) in the QSH anti-wires devices. The interesting feature of this design is that the presence of MBS could be directly observed by the sign of multiterminal conductance in the absence of ferromagnetic contacts.
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| Outline of Final Research Achievements |
We focus on van der Waals heterostructures combining graphene with Bi2-xSbxTe3-ySey thin film (BSTS), one of the best three-dimensional topological insulators (3D-TIs). We have shown that graphene is a good platform for growing high quality BSTS films with thicknesses in the range of 10 to 30 nm. When the thickness of the BSTS films is below 10 nm, the proximity effect induced enhancement of the spin-orbit interaction at the interface of graphene and BSTS ultrathin films supports the emergence of helical edge states along the edge.
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| Academic Significance and Societal Importance of the Research Achievements |
The development of a highly controllable fabrication method for 2D-TIs holds significant potential for the next generation of electronic devices. Moreover, helical edge states is an idea platform to discovery Majorana fermions that can become a future material for quantum computer.
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