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Spin polarization of the quantum spin Hall edge states

Abstract

The prediction and experimental verification of the quantum spin Hall state marked the discovery of a new state of matter now known as topological insulators. Two-dimensional topological insulators exhibit the quantum spin-Hall effect, characterized by gapless spin-polarized counter-propagating edge channels. Whereas the helical character of these edge channels is now well established, experimental confirmation that the transport in the edge channels is spin polarized is still outstanding. We report experiments on nanostructures fabricated from HgTe quantum wells with an inverted band structure, in which a split gate technique allows us to combine both quantum spin Hall and metallic spin Hall transport in a single device. In these devices, the quantum spin Hall effect can be used as a spin current injector and detector for the metallic spin Hall effect, and vice versa, allowing for an all-electrical detection of spin polarization.

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Figure 1: Schematic layout of the two experiments on split-gated H-bar devices discussed in this paper.
Figure 2: Characterization of devices.
Figure 3: Experimental non-local resistance data corresponding to the measurement configuration of Fig. 1a.
Figure 4: Experimental non-local resistance data corresponding to the measurement configuration of Fig. 1b.
Figure 5: Semiclassical Monte Carlo simulation of the non-local resistance.

References

  1. Bernevig, B. A., Hughes, T. L. & Zhang, S. C. Quantum spin Hall effect and topological phase transition in HgTe quantum wells. Science 314, 1757–1761 (2006).

    ADS  Article  Google Scholar 

  2. König, M. et al. Quantum spin Hall insulator state in HgTe quantum wells. Science 318, 766–770 (2007).

    ADS  Article  Google Scholar 

  3. König, M. et al. The quantum spin Hall effect: Theory and experiment. J. Phys. Soc. Jpn 77, 031007 (2008).

    ADS  Article  Google Scholar 

  4. Kane, C. L. & Mele, E. J. Quantum spin Hall effect in graphene. Phys. Rev. Lett. 95, 226801 (2005).

    ADS  Article  Google Scholar 

  5. Bernevig, B. A. & Zhang, S. C. Quantum spin Hall effect. Phys. Rev. Lett. 96, 106802 (2006).

    ADS  Article  Google Scholar 

  6. Wu, C. J., Bernevig, B. A. & Zhang, S. C. Helical liquid and the edge of quantum spin Hall systems. Phys. Rev. Lett. 96, 106401 (2006).

    ADS  Article  Google Scholar 

  7. Xu, C. & Moore, J. Stability of the quantum spin Hall effect: Effects of interactions, disorder, and topology. Phys. Rev. B 73, 045322 (2006).

    ADS  Article  Google Scholar 

  8. Maciejko, J. et al. Kondo effect in the helical edge liquid of the quantum spin Hall state. Phys. Rev. Lett. 102, 256803 (2009).

    ADS  Article  Google Scholar 

  9. Roth, A. et al. Nonlocal transport in the quantum spin Hall state. Science 325, 294–297 (2009).

    ADS  Article  Google Scholar 

  10. Büttiker, M. Edge-state physics without magnetic fields. Science 325, 278–279 (2009).

    Article  Google Scholar 

  11. Hankiewicz, E. M., Molenkamp, L. W., Jungwirth, T. & Sinova, J. Manifestation of the spin Hall effect through charge-transport in the mesoscopic regime. Phys. Rev. B 70, 241301 (2004).

    ADS  Article  Google Scholar 

  12. Valenzuela, S. O. & Tinkham, M. Direct electronic measurement of the spin Hall effect. Nature 442, 176–179 (2006).

    ADS  Article  Google Scholar 

  13. Brüne, C. et al. Evidence for the ballistic intrinsic spin Hall effect in HgTe nanostructures. Nature Phys. 6, 448–454 (2010).

    ADS  Article  Google Scholar 

  14. Rothe, D. G. et al. Fingerprint of different spin-orbit terms for spin transport in HgTe quantum wells. New J. Phys. 12, 065012 (2010).

    ADS  Article  Google Scholar 

  15. Novik, E. G. et al. Band structure of semimagnetic Hg1−yMnyTe quantum wells. Phys. Rev. B 72, 035321 (2005).

    ADS  Article  Google Scholar 

  16. Hinz, J. et al. control of the giant Rashba effect in HgTe quantum wells. Semicond. Sci. Technol. 21, 501–506 (2006).

    ADS  Article  Google Scholar 

  17. Büttiker, M. Four-terminal phase-coherent conductance. Phys. Rev. Lett. 57, 1761–1764 (1986).

    ADS  Article  Google Scholar 

  18. Büttiker, M. Symmetry of electrical conduction. IBM J. Res. Dev. 32, 317–334 (1988).

    Article  Google Scholar 

  19. Beenakker, C. W. J. & van Houten, H. Billiard model of a ballistic multiprobe conductor. Phys. Rev. Lett. 63, 1857–1860 (1989).

    ADS  Article  Google Scholar 

  20. Sundaram, G. & Niu, Q. Wavepacket dynamics in slowly perturbed crystals: Gradient corrections and Berry-phase effects. Phys. Rev. B 59, 14915–14925 (1999).

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We thank M. Leberecht and R. Rommel for assistance in some of the experiments andE. G. Novik for discussions of the band structure. We gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft (Schwerpunkt Spintronik) under grants HA 5893/1-2 (E.M.H.) and BU 1113/3-1 (H.B.), the German-Israeli Foundation (I-881-138.7/2005) the DFG-JST joint research project Topological Electronics, the National Science and Engineering Research Council (NSERC) of Canada and the Stanford Graduate Fellowship Program (SGF). S-C.Z. is supported by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract DE-AC02-76SF00515 and by the Keck Foundation. We agree the Leibniz Rechenzentrum Munich, the facilities of the Shared Hierarchical Academic Research Computing Network (www.sharcnet.ca) and the computing cluster of the Stanford Institute for Materials and Energy Science at the SLAC National Accelerator Laboratory for providing computer resources.

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C.B., A.R., H.B. and L.W.M. have contributed to the experiments, E.M.H., J.M., X-L.Q. and S-C.Z. contributed to the theory. All authors have participated in the interpretation of the experiments. The paper was written by C.B., J.M., E.M.H., S-C.Z and L.W.M., and the Supplementary Information by J.M., X.L.Q. and E.M.H.

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Correspondence to Laurens W. Molenkamp.

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The authors declare no competing financial interests.

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Brüne, C., Roth, A., Buhmann, H. et al. Spin polarization of the quantum spin Hall edge states. Nature Phys 8, 485–490 (2012). https://doi.org/10.1038/nphys2322

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