| 1. |
- Wang, Xingjun, et al.
(författare)
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Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor.
- 2009
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-1122 .- 1476-4660. ; 8:3, s. 198-202
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Tidskriftsartikel (refereegranskat)abstract
- Generating, manipulating and detecting electron spin polarization and coherence at room temperature is at the heart of future spintronics and spin-based quantum information technology. Spin filtering, which is a key issue for spintronic applications, has been demonstrated by using ferromagnetic metals, diluted magnetic semiconductors, quantum point contacts, quantum dots, carbon nanotubes, multiferroics and so on. This filtering effect was so far restricted to a limited efficiency and primarily at low temperatures or under a magnetic field. Here, we provide direct and unambiguous experimental proof that an electron-spin-polarized defect, such as a Ga(i) self-interstitial in dilute nitride GaNAs, can effectively deplete conduction electrons with an opposite spin orientation and can thus turn the non-magnetic semiconductor into an efficient spin filter operating at room temperature and zero magnetic field. This work shows the potential of such defect-engineered, switchable spin filters as an attractive alternative to generate, amplify and detect electron spin polarization at room temperature without a magnetic material or external magnetic fields.
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| 2. |
- Zhao, F, et al.
(författare)
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Electron spin control in dilute nitride semiconductors
- 2009
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Ingår i: JOURNAL OF PHYSICS-CONDENSED MATTER. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 21:17, s. 174211-
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Tidskriftsartikel (refereegranskat)abstract
- We report on a study of spin-dependent recombination processes (SDR) for conduction band electrons on deep paramagnetic centers in a series of GaAs1-yNy epilayers by time-resolved optical orientation experiments. We demonstrate that this dilute nitride compound can be used as an effective electron spin filter under a polarized optical excitation of appropriate intensity. This optimum intensity can moreover be controlled by adjusting the nitrogen composition in the layer.
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| 3. |
- Puttisong, Yuttapoom, et al.
(författare)
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Electron spin filtering by thin GaNAs/GaAs multiquantum wells
- 2010
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 96:5, s. 052104-
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Tidskriftsartikel (refereegranskat)abstract
- Effectiveness of the recently discovered defect-engineered spin-filtering effect is closely examined in GaNAs/GaAs multiquantum wells (QWs) as a function of QW width. In spite of narrow well widths of 3-9 nm, rather efficient spin filtering is achieved at room temperature. It leads to electron spin polarization larger than 18% and an increase in photoluminescence intensity by 65% in the 9 nm wide QWs. A weaker spin filtering effect is observed in the narrower QWs, mainly due to a reduced sheet concentration of spin-filtering defects (e.g., Ga-i interstitial defects).
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| 4. |
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| 5. |
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| 6. |
- Wang, Xingjun, et al.
(författare)
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Efficient Spin Filter Based on Non-Magnetic Semiconductor GaNAs
- 2009
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Ingår i: Integrated Photonics and Nanophotonics Research and Applications/Nonlinear Optics/Slow and Fast Light. - 9781557528735 ; , s. IWD4-
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Konferensbidrag (refereegranskat)abstract
- We provide experimental demonstration of a novel defect-engineered, efficient and switchable spin filter from GaNAs to generate, amplify and detect electron spin polarization at room temperature without a magnetic material or external magnetic fields.
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| 7. |
- Wang, Xingjun, 1972-, et al.
(författare)
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Generating strong electron spin polarization at room temperature in GaNAs via spin-dependent recombination
- 2008
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Ingår i: 5th International Conference on Physics and Applications of Spin-related Phenomena in Semiconductors PASPS V,2008.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The issues of generating and maintaining carrier spin polarization in semiconductors have attracted intense research efforts, not only due to their importance for future applications in spintronics but also due to the intriguing physics underpinning spin-dependent phenomena. Entering the family of semiconductors that exhibit attractive spin-dependent properties, Ga(In)NAs was most recently found to exhibit strong spin polarization of conducting electrons at room temperature upon N incorporation with an extremely long apparent spin lifetime. In this work we have uncovered the origin of the astonishing effect as being due to strong spin dependent recombination (SDR) via defects, by a combination of optical orientation and optically detected magnetic resonance (ODMR) studies. We were able to identify Ga self-interstitials and an As antisite complex to be the dominant defects participating in the SDR process. The involvement of these defects were unambiguously established by their unique spin-resonance signatures derived from the hyperfine interaction between the localized unpaired electron spin and nuclear spins (I=3/2) of the As and Ga atom - the core of the defects. These defects dominate in carrier capture and recombination leading to the observed strong dynamic polarization of electron spins. Further confirmation was found by the effects of growth conditions and post-growth treatments on the defect density that were closely correlated with the electron spin polarization.
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