2010 Fiscal Year Final Research Report
Electrical detection and control of spin current by using spin orbit interaction
Project Area | Creation and control of spin current |
Project/Area Number |
19048005
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Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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Allocation Type | Single-year Grants |
Review Section |
Science and Engineering
|
Research Institution | Tohoku University |
Principal Investigator |
NITTA Junsaku 東北大学, 大学院・工学研究科, 教授 (00393778)
|
Co-Investigator(Kenkyū-buntansha) |
KOHDA Makoto 東北大学, 大学院・工学研究科, 准教授 (00420000)
|
Project Period (FY) |
2007 – 2010
|
Keywords | スピン流 / スピン軌道相互作用 |
Research Abstract |
Spin orbit interaction (SOI) plays an important role for electrical manipulation of spins. However, the direction of the effective magnetic field induced by the SOI delends on the momentum direction. Therefore, spin orientation is randomized after scattering events. This is the so-called spin relaxation. Spin relaxation is suppressed when the Rashba SOI strength is equal to that of the Dresselhaus SOI since the effective magnetic field direction becomes uniaxial. We have found that spin relaxation rate depends on the crystal orientations in InGaAs wires. This indicates that both Rashba and Dresselhaus SOIs coexist in an InGaAs/InAlAs heterostructure. The Dresselhaus SOI strength depends on the thickness of quantum well (QW). In a thinnest InGaAs QW, remarkable suppression of spin relaxation is observed by tuning the Rashba SOI through the gate voltage. This suggests the gate-controlled persistent spin helix state.
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