| CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY |
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Spin Injection from Ferromagnetic Metal Directly into Non-Magnetic Semiconductor under Different Injection Currents |
DENG Ning1,2, TANG Jian-Shi2, ZHANG Lei1, ZHANG Shu-Chao1, CHEN Pei-Yi1 |
| 1Institute of Microelectronics, Tsinghua University, Beijing 100084 2Department of Electrical Engineering, UCLA, California, USA |
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| Cite this article: |
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DENG Ning, TANG Jian-Shi, ZHANG Lei et al 2010 Chin. Phys. Lett. 27 098501 |
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Abstract For ferromagnetic metal (FM)/semiconductor (SC) structure with ohmic contact, the effect of carrier polarization in the semiconductor combined with drift part of injection current on current polarization is investigated. Based on the general model we established here, spin injection efficiency under different injection current levels is calculated. Under a reasonable high injection current, current polarization in the semiconductor is actually much larger than that predicted by the conductivity mismatch model because the effect of carrier polarization is enhanced by the increasing drift current. An appreciable current polarization of 1% could be achieved for the FM/SC structure via ohmic contact, which means that efficient spin injection from FM into SC via ohmic contact is possible. The reported dependence of current polarization on temperature is verified quantitatively. To achieve even larger spin injection efficiency, a gradient doping semiconductor is suggested to enhance the drift current effect.
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| Keywords:
85.75.-d
75.40.Gb
72.25.Pn
72.80.Cw
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Received: 06 April 2010
Published: 25 August 2010
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| PACS: |
85.75.-d
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(Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields)
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75.40.Gb
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(Dynamic properties?)
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72.25.Pn
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(Current-driven spin pumping)
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72.80.Cw
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(Elemental semiconductors)
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