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Highly efficient and tunable spin-to-charge conversion through Rashba coupling at oxide interfaces

Abstract

The spin–orbit interaction couples the electrons’ motion to their spin. As a result, a charge current running through a material with strong spin–orbit coupling generates a transverse spin current (spin Hall effect, SHE) and vice versa (inverse spin Hall effect, ISHE). The emergence of SHE and ISHE as charge-to-spin interconversion mechanisms offers a variety of novel spintronic functionalities and devices, some of which do not require any ferromagnetic material. However, the interconversion efficiency of SHE and ISHE (spin Hall angle) is a bulk property that rarely exceeds ten percent, and does not take advantage of interfacial and low-dimensional effects otherwise ubiquitous in spintronic hetero- and mesostructures. Here, we make use of an interface-driven spin–orbit coupling mechanism—the Rashba effect—in the oxide two-dimensional electron system (2DES) LaAlO3/SrTiO3 to achieve spin-to-charge conversion with unprecedented efficiency. Through spin pumping, we inject a spin current from a NiFe film into the oxide 2DES and detect the resulting charge current, which can be strongly modulated by a gate voltage. We discuss the amplitude of the effect and its gate dependence on the basis of the electronic structure of the 2DES and highlight the importance of a long scattering time to achieve efficient spin-to-charge interconversion.

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Figure 1: Characterization of NiFe/LAO//STO system.
Figure 2: Ferromagnetic resonance in NiFe/LAO//STO.
Figure 3: Spin-to-charge conversion in LAO//STO 2DES.
Figure 4: Gate control of the inverse Edelstein effect in LAO//STO 2DES.

References

  1. 1

    Imada, M., Fujimori, A. & Tokura, Y. Metal–insulator transitions. Rev. Mod. Phys. 70, 1039–1263 (1998).

    CAS  Article  Google Scholar 

  2. 2

    Bibes, M. & Barthélémy, A. Oxide spintronics. IEEE Trans. Electron Devices 54, 1003–1023 (2007).

    CAS  Article  Google Scholar 

  3. 3

    Bowen, M. et al. Nearly total spin polarization in La2/3Sr1/3MnO3 from tunneling experiments. Appl. Phys. Lett. 82, 233–235 (2003).

    CAS  Article  Google Scholar 

  4. 4

    Chu, Y. et al. Electric-field control of local ferromagnetism using a magnetoelectric multiferroic. Nat. Mater. 7, 478–482 (2008).

    CAS  Article  Google Scholar 

  5. 5

    Liu, L. et al. Spin-torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).

    CAS  Article  Google Scholar 

  6. 6

    Demidov, V. E., Urazhdin, S., Edwards, E. R. J. & Demokritov, S. O. Wide-range control of ferromagnetic resonance by spin Hall effect. Appl. Phys. Lett. 99, 2013–2016 (2011).

    Google Scholar 

  7. 7

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

    Article  Google Scholar 

  8. 8

    Hoffmann, A. Spin Hall effects in metals. IEEE Trans. Magn. 49, 5172–5193 (2013).

    CAS  Article  Google Scholar 

  9. 9

    Niimi, Y. & Otani, Y. Reciprocal spin Hall effects in conductors with strong spin–orbit coupling: a review. Rep. Prog. Phys. 78, 124501 (2015).

    Article  Google Scholar 

  10. 10

    Sinova, J., Valenzuela, S. O., Wunderlich, J., Back, C. H. & Jungwirth, T. Spin Hall effects. Rev. Mod. Phys. 87, 1213–1260 (2015).

    Article  Google Scholar 

  11. 11

    Witczak-Krempa, W., Chen, G., Kim, Y. B. & Balents, L. Correlated quantum phenomena in the strong spin–orbit regime. Annu. Rev. Condens. Matter Phys. 5, 57–82 (2014).

    CAS  Article  Google Scholar 

  12. 12

    Hwang, H. Y. et al. Emergent phenomena at oxide interfaces. Nat. Mater. 11, 103–113 (2012).

    CAS  Article  Google Scholar 

  13. 13

    Ohtomo, A. & Hwang, H. Y. A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423–426 (2004).

    CAS  Article  Google Scholar 

  14. 14

    Thiel, S., Hammerl, G., Schmehl, A., Schneider, C. W. & Mannhart, J. Tunable quasi-two-dimensional electron gases in oxide heterostructures. Science 313, 1942–1945 (2006).

    CAS  Article  Google Scholar 

  15. 15

    Caviglia, A. D. et al. Tunable Rashba spin–orbit interaction at oxide interfaces. Phys. Rev. Lett. 104, 126803 (2010).

    CAS  Article  Google Scholar 

  16. 16

    Ben Shalom, M., Sachs, M., Rakhmilevitch, D., Palevski, A. & Dagan, Y. Tuning spin–orbit coupling and superconductivity at the SrTiO3/LaAlO3 interface: a magnetotransport study. Phys. Rev. Lett. 104, 126802 (2010).

    CAS  Article  Google Scholar 

  17. 17

    Caprara, S., Peronaci, F. & Grilli, M. Intrinsic instability of electronic interfaces with strong Rashba coupling. Phys. Rev. Lett. 109, 196401 (2012).

    CAS  Article  Google Scholar 

  18. 18

    Bucheli, D., Grilli, M., Peronaci, F., Seibold, G. & Caprara, S. Phase diagrams of voltage-gated oxide interfaces with strong Rashba coupling. Phys. Rev. B 89, 195448 (2014).

    Article  Google Scholar 

  19. 19

    Seibold, G., Caprara, S., Grilli, M. & Raimondi, R. Intrinsic spin Hall effect in systems with striped spin–orbit coupling. Europhys. Lett. 112, 17004 (2015).

    Article  Google Scholar 

  20. 20

    Bychkov, Y. A. & Rashba, E. I. Properties of a 2D electron gas with lifted spectral degeneracy. JETP Lett. 39, 78–81 (1984).

    Google Scholar 

  21. 21

    Manchon, A., Koo, H. C., Nitta, J., Frolov, S. M. & Duine, R. A. New perspectives for Rashba spin–orbit coupling. Nat. Mater. 14, 871–882 (2015).

    CAS  Article  Google Scholar 

  22. 22

    Edelstein, V. M. Spin polarization of conduction electrons induced by electric current in two-dimensional asymmetric electron systems. Solid State Commun. 73, 233–235 (1990).

    Article  Google Scholar 

  23. 23

    Aronov, A. G. & Lyanda-Geller, Y. B. Nuclear electric resonance and orientation of carrier spins by an electric field. JETP Lett. 50, 431–433 (1989).

    Google Scholar 

  24. 24

    Rojas-Sánchez, J. C. et al. Spin-to-charge conversion using Rashba coupling at the interface between non-magnetic materials. Nat. Commun. 4, 2944 (2013).

    Article  Google Scholar 

  25. 25

    Lesne, E. et al. Suppression of the critical thickness threshold for conductivity at the LaAlO3/SrTiO3 interface. Nat. Commun. 5, 4291 (2014).

    CAS  Article  Google Scholar 

  26. 26

    Tserkovnyak, Y., Brataas, A. & Bauer, G. E. W. Enhanced Gilbert damping in thin ferromagnetic films. Phys. Rev. Lett. 88, 117601 (2002).

    Article  Google Scholar 

  27. 27

    Shaw, J. M., Nembach, H. T., Silva, T. J. & Boone, C. T. Precise determination of the spectroscopic g-factor by use of broadband ferromagnetic resonance spectroscopy. J. Appl. Phys. 114, 243906 (2013).

    Article  Google Scholar 

  28. 28

    Azevedo, A., Vilela-Leão, L., Rodríguez-Suárez, R., Lacerda Santos, A. & Rezende, S. Spin pumping and anisotropic magnetoresistance voltages in magnetic bilayers: theory and experiment. Phys. Rev. B 83, 144402 (2011).

    Article  Google Scholar 

  29. 29

    Harder, M., Cao, Z. X., Gui, Y. S., Fan, X. L. & Hu, C.-M. Analysis of the line shape of electrically detected ferromagnetic resonance. Phys. Rev. B 84, 054423 (2011).

    Article  Google Scholar 

  30. 30

    Mosendz, O., Pearson, J. E., Fradin, F. Y., Bader, S. D. & Hoffmann, A. Suppression of spin-pumping by a MgO tunnel-barrier. Appl. Phys. Lett. 96, 2010–2013 (2010).

    Article  Google Scholar 

  31. 31

    Reyren, N. et al. Gate-controlled spin injection at LaAlO3/SrTiO3 interfaces. Phys. Rev. Lett. 108, 186802 (2012).

    CAS  Article  Google Scholar 

  32. 32

    Rojas-Sánchez, J.-C. et al. Spin to charge conversion at room temperature by spin pumping into a new type of topological insulator: α-Sn films. Phys. Rev. Lett. 116, 096602 (2016).

    Article  Google Scholar 

  33. 33

    Shen, K., Vignale, G. & Raimondi, R. Microscopic theory of the inverse Edelstein effect. Phys. Rev. Lett. 112, 096601 (2014).

    Article  Google Scholar 

  34. 34

    Jamali, M. et al. Giant spin pumping and inverse spin Hall effect in the presence of surface and bulk spin–orbit coupling of topological insulator Bi2Se3 . Nano Lett. 15, 7126–7132 (2015).

    CAS  Article  Google Scholar 

  35. 35

    Nomura, A., Tashiro, T., Nakayama, H. & Ando, K. Temperature dependence of inverse Rashba–Edelstein effect at metallic interface. Appl. Phys. Lett. 106, 212403 (2015).

    Article  Google Scholar 

  36. 36

    Fête, A. Magnetotransport Experiments at the LaAlO3/SrTiO3 Interface (Université de Genève, 2014).

    Google Scholar 

  37. 37

    Shanavas, K. V., Popović, Z. S. & Satpathy, S. Theoretical model for Rashba spin–orbit interaction in d electrons. Phys. Rev. B 90, 165108 (2014).

    Article  Google Scholar 

  38. 38

    Hurand, S. et al. Field-effect control of superconductivity and Rashba spin–orbit coupling in top-gated LaAlO3/SrTiO3 devices. Sci. Rep. 5, 12751 (2015).

    CAS  Article  Google Scholar 

  39. 39

    Joshua, A., Pecker, S., Ruhman, J., Altman, E. & Ilani, S. A universal critical density underlying the physics of electrons at the LaAlO3/SrTiO3 interface. Nat. Commun. 3, 1129 (2012).

    Article  Google Scholar 

  40. 40

    Liang, H. et al. Nonmonotonically tunable Rashba spin–orbit coupling by multiple-band filling control in SrTiO3-based interfacial electron gases. Phys. Rev. B 92, 075309 (2015).

    Article  Google Scholar 

  41. 41

    King, P. D. C. et al. Quasiparticle dynamics and spin–orbital texture of the SrTiO3 two-dimensional electron gas. Nat. Commun. 5, 3414 (2014).

    CAS  Article  Google Scholar 

  42. 42

    Zhong, Z., Tóth, A. & Held, K. Theory of spin–orbit coupling at LaAlO3/SrTiO3 interfaces and SrTiO3 . Phys. Rev. B 87, 161102 (2013).

    Article  Google Scholar 

  43. 43

    Bibes, M. et al. Towards electrical spin injection into LaAlO3/SrTiO3 . Phil. Trans. R. Soc. A 370, 4958–4971 (2012).

    CAS  Article  Google Scholar 

  44. 44

    Datta, S. & Das, B. Electronic analog of the electro-optic modulator. Appl. Phys. Lett. 56, 665–667 (1990).

    CAS  Article  Google Scholar 

  45. 45

    Xu, W. J. et al. Anomalous Hall effect in Fe/Gd bilayers. Europhys. Lett. 90, 27004 (2010).

    Article  Google Scholar 

Download references

Acknowledgements

Research at CNRS/Thales received support from the ERC Consolidator Grant #615759 “MINT” and the region Île-de-France DIM “Oxymore” (project NEIMO). Support from the ANR SOspin and ANR Lacunes projects is also acknowledged. H.N. was partly supported by the Leading Young Researcher Overseas Visit Program, JSPS Grant-in-Aid for Scientific Research (B) (#15H03548). Authors are grateful to Y. Kodama (Tohoku University, Japan) for TEM observation and to N. Reyren for his help at the early stage of the project.

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M.B., L.V., E.L., J.C.R.-S., H.J. and J.-M.G. conceived and designed the experiment. M.B. and L.V. supervised the project. E.L. and D.C.V. grew the samples with the help of H.N. and E.J., and performed the d.c. transport experiments and analysed the data. E.L., J.C.R.-S., Y.F., S.O. and J.-M.G. performed the room-temperature FMR measurements and analysed the data. Y.F., S.O., J.C.R.-S., E.L. and L.V. performed the low-temperature spin-pumping experiments and analysed the data with the help of M.B., H.J. and A.F. M.B. and E.L. wrote the manuscript, with inputs from H.J. All authors discussed the data and contributed to the manuscript.

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Correspondence to J. C. Rojas-Sánchez or M. Bibes.

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Lesne, E., Fu, Y., Oyarzun, S. et al. Highly efficient and tunable spin-to-charge conversion through Rashba coupling at oxide interfaces. Nature Mater 15, 1261–1266 (2016). https://doi.org/10.1038/nmat4726

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