Abstract
Recent discoveries of phenomena that relate electronic transport in solids to the spin angular momentum of the electrons are the fundamentals of spin electronics (spintronics). The first proposed conceptual spintronic device, the spin field-effect transistor—which has not yet been successfully implemented—requires the creation and detection of spin-polarized currents in a semiconductor. Whereas electrical spin injection from a ferromagnetic metal into GaAs has been achieved recently, the detection techniques used up to now have drawbacks like the requirement of large magnetic fields or limited information about the spin polarization in the semiconductor. Here we introduce a method that, by observation across a cleaved edge, enables us to directly visualize fully remanent electrical spin injection into bulk GaAs from a ferromagnetic contact, to image the spin-density distribution in the semiconductor in a cross-sectional view and to separate the effects of spin diffusion and electron drift.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$209.00 per year
only $17.42 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Žutić, I., Fabian, J. & Das Sarma, S. Spintronics: Fundamental and applications. Rev. Mod. Phys. 76, 323–410 (2004).
Datta, S. & Das, B. Electronic analog of the electro-optic modulator. Appl. Phys. Lett. 56, 665–667 (1990).
Zhu, H. J. et al. Room-temperature spin injection from Fe into GaAs. Phys. Rev. Lett. 87, 016601 (2001).
Hanbicki, A. T., Jonker, B. T., Itskos, G., Kioseoglou, G. & Petrou, A. Efficient electrical spin injection from a magnetic metal/tunnel barrier contact into a semiconductor. Appl. Phys. Lett. 80, 1240–1242 (2002).
Adelmann, C., Lou, X., Strand, J., Palmstrøm, C. J. & Crowell, P. A. Spin injection and relaxation in ferromagnet–semiconductor heterostructures. Phys. Rev. B 71, 121301 (2005).
Crooker, S. A. et al. Imaging spin transport in lateral ferromagnet/semiconductor structures. Science 309, 2191–2195 (2005).
Motsnyi, F. et al. Electrical spin injection in a ferromagnet/tunnel barrier/semiconductor heterostructure. Appl. Phys. Lett. 81, 265–267 (2002).
Jiang, X. et al. Highly spin-polarized room-temperature tunnel injector for semiconductor spintronics using MgO (100). Phys. Rev. Lett. 94, 056601 (2005).
Adelmann, C. et al. Spin injection from a perpendicular magnetized ferromagnetic δ-MnGa into (Al,Ga)As heterostructures. Appl. Phys. Lett. 89, 112511 (2006).
Gerhardt, N. C. et al. Electron spin injection into GaAs from ferromagnetic contacts in remanence. Appl. Phys. Lett. 87, 032502 (2005).
van ’t Erve, O. M. J., Kioseoglou, G., Hanbicki, A. T., Li, C. H. & Jonker, B. T. Remanent electrical spin injection from Fe into AlGaAs/GaAs light emitting diodes. Appl. Phys. Lett. 89, 072505 (2006).
Lou, X. et al. Electrical detection of spin accumulation at a ferromagnet–semiconductor interface. Phys. Rev. Lett. 96, 176603 (2006).
Padovani, F. A. & Stratton, R. Field and thermionic-field emission in Schottky barriers. Solid-State Electron. 9, 695 (1966).
Bayreuther, G., Dumm, M., Uhl, B., Meier, R. & Kipferl, W. Magnetocrystalline volume and interface anisotropies in epitaxial films: Universal relation and Néel’s model. J. Appl. Phys. 93, 8230–8235 (2003).
Yu, Z. G. & Flatté, M. E. Spin diffusion and injection in semiconductor structures: Electric field effects. Phys. Rev. B 66, 235302 (2002).
Aronov, A. G. & Pikus, G. E. Spin injection into semiconductors. Sov. Phys. Semicond. 10, 698–700 (1976).
Paget, D. & Berkovits, V. L. in Optical Orientation (eds Meier, F. & Zakharchenya, B. P.) Ch. 9, 381–422 (North-Holland, Amsterdam, 1984).
Kikkawa, J. M. & Awschalom, D. D. Resonant spin amplification in n-type GaAs. Phys. Rev. Lett. 80, 4313–4316 (1998).
Dzhioev, R. I. et al. Low-temperature spin relaxation in n-type GaAs. Phys. Rev. B 66, 245204 (2002).
Ciuti, C., McGuire, J. P. & Sham, L. J. Spin polarization of semiconductor carriers by reflection off a ferromagnet. Phys. Rev. Lett. 89, 156601 (2002).
Osipov, V. V. & Bratkovsky, A. M. Spin accumulation in degenerate semiconductors near modified Schottky contact with ferromagnets: Spin injection and extraction. Phys. Rev. B 72, 115322 (2005).
Lou, X. et al. Electrical detection of spin transport in lateral ferromagnet–semiconductor devices. Nature Phys. 3, 197–202 (2007).
Dery, H. & Sham, L. J. Spin extraction theory and its relevance to spintronics. Phys. Rev. Lett. 98, 046602 (2007).
Bournel, A., Dollfus, P., Bruno, P. & Hesto, P. Spin polarized transport in 1D and 2D semiconductor heterostructures. Mater. Sci. Forum 297–298, 205–212 (1999).
Bournel, A., Dollfus, P., Bruno, P. & Hesto, P. Gate-induced spin precession in an In0.53Ga0.47As two dimensional electron gas. Eur. Phys. J. AP 4, 1–4 (1998).
Moosbühler, R., Bensch, F., Dumm, M. & Bayreuther, G. Epitaxial Fe films on GaAs(001): Does the substrate surface reconstruction affect the uniaxial magnetic anisotropy? J. Appl. Phys. 91, 8757–8759 (2002).
Acknowledgements
This work has been supported by the Deutsche Forschungsgemeinschaft (DFG) under FOR 370 and SFB 689. We thank B. Muermann and J. Ehehalt for assistance with programming some of the measurement procedures, P. Chen for characterization of the GaAs materials and J. Fabian for discussions.
Author information
Authors and Affiliations
Contributions
P.K. designed and carried out the experiments, analysed the data and prepared the manuscript; M.B. conceived the main experiment, developed the theoretical data analysis and contributed to the manuscript; M.S. carried out the SQUID measurements and contributed to the manuscript; A.S. carried out part of the sample preparation; D.S. grew the semiconductor materials; W.W. devised the project and contributed materials; C.H.B. provided support for the optical measurements and contributed to the manuscript; G.B. devised the project, contributed to the data analysis and wrote the paper.
Corresponding author
Supplementary information
Supplementary Information
Supplementary Figures 1 and 2 (PDF 88 kb)
Rights and permissions
About this article
Cite this article
Kotissek, P., Bailleul, M., Sperl, M. et al. Cross-sectional imaging of spin injection into a semiconductor. Nature Phys 3, 872–877 (2007). https://doi.org/10.1038/nphys734
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nphys734
This article is cited by
-
Room-temperature polarized spin-photon interface based on a semiconductor nanodisk-in-nanopillar structure driven by few defects
Nature Communications (2018)
-
Spin photocurrent spectra induced by Rashba- and Dresselhaus-type circular photogalvanic effect at inter-band excitation in InGaAs/GaAs/AlGaAs step quantum wells
Nanoscale Research Letters (2014)
-
Demonstration of the spin solar cell and spin photodiode effect
Nature Communications (2013)
-
Direct measurement of the electronic spin diffusion length in a fully functional organic spin valve by low-energy muon spin rotation
Nature Materials (2009)