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Electric-field-induced superconductivity in an insulator

Abstract

Electric field control of charge carrier density has long been a key technology to tune the physical properties of condensed matter, exploring the modern semiconductor industry. One of the big challenges is to increase the maximum attainable carrier density so that we can induce superconductivity in field-effect-transistor geometry. However, such experiments have so far been limited to modulation of the critical temperature in originally conducting samples because of dielectric breakdown1,2,3,4. Here we report electric-field-induced superconductivity in an insulator by using an electric-double-layer gating in an organic electrolyte5. Sheet carrier density was enhanced from zero to 1014 cm−2 by applying a gate voltage of up to 3.5 V to a pristine SrTiO3 single-crystal channel. A two-dimensional superconducting state emerged below a critical temperature of 0.4 K, comparable to the maximum value for chemically doped bulk crystals6, indicating this method as promising for searching for unprecedented superconducting states.

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Figure 1: Schematic structures and current–voltage characteristics of an electric-double-layer field-effect transistor.
Figure 2: Electrical properties of accumulated SrTiO3 surface layer.
Figure 3: Superconducting properties and electronic structure of the SrTiO3 channel under a gate bias voltage VG=3 V.
Figure 4: Gate voltage, VG, dependence of transport properties and electronic parameters deduced with the triangular-potential approximation.

References

  1. Ahn, C. H. et al. Electrostatic modulation of superconductivity in ultrathin GdBa2Cu3O7−x films. Science 284, 1152–1155 (1999).

    Article  CAS  Google Scholar 

  2. Ahn, C. H., Triscone, J.-M. & Mannhart, J. Electric field effect in correlated oxide systems. Nature 424, 1015–1018 (2003).

    Article  CAS  Google Scholar 

  3. Takahashi, K. S. et al. Electrostatic modulation of the electronic properties of Nb-doped SrTiO3 superconducting films. Appl. Phys. Lett. 84, 1722–1724 (2004).

    Article  CAS  Google Scholar 

  4. Takahashi, K. S. et al. Local switching of two-dimensional superconductivity using the ferroelectric field effect. Nature 441, 195–198 (2006).

    Article  CAS  Google Scholar 

  5. Kötz, R. & Carlen, M. Principles and applications of electrochemical capacitors. Electrochim. Acta 45, 2483–2498 (2000).

    Article  Google Scholar 

  6. Schooley, J. F. et al. Dependence of the superconducting transition temperature on carrier concentration in semiconducing SrTiO3 . Phys. Rev. Lett. 14, 305–307 (1965).

    Article  CAS  Google Scholar 

  7. Ohno, H. et al. Electric-field control of ferromagnetism. Nature 408, 944–946 (2000).

    Article  CAS  Google Scholar 

  8. Glover, R. E. & Sherrill, M. D. Changes in superconducting critical temperature produced by electrostatic charging. Phys. Rev. Lett. 5, 248–250 (1960).

    Article  CAS  Google Scholar 

  9. Ueno, K. et al. Field-effect transistor on SrTiO3 with sputtered Al2O3 gate insulator. Appl. Phys. Lett. 83, 1755–1757 (2003).

    Article  CAS  Google Scholar 

  10. Shibuya, K. et al. Field-effect modulation of the transport properties of nondoped SrTiO3 . Appl. Phys. Lett. 88, 212116 (2006).

    Article  Google Scholar 

  11. Nakamura, H. et al. Low temperature metallic state induced by electrostatic carrier doping of SrTiO3 . Appl. Phys. Lett. 89, 133504 (2006).

    Article  Google Scholar 

  12. Sato, T., Shibuya, K., Ohnishi, T., Nishio, K. & Lippmaa, M. Fabrication of SrTiO3 field effect transistors with SrTiO3−δ source and drain electrodes. Jpn. J. Appl. Phys. 46, L515–L518 (2007).

    Article  CAS  Google Scholar 

  13. Dhoot, A. S. et al. Beyond the metal–insulator transition in polymer electrolyte gated polymer field-effect transistors. Proc. Natl Acad. Sci 103, 11834–11837 (2006).

    Article  CAS  Google Scholar 

  14. Panzer, M. J. & Frisbie, C. D. High carrier density and metallic conductivity in poly(3-hexylthiophene) achieved by electrostatic charge injection. Adv. Funct. Mater. 16, 1051–1056 (2006).

    Article  CAS  Google Scholar 

  15. Misra, R., McCarthy, M. & Hebard, A. F. Electric field gating with ionic liquids. Appl. Phys. Lett. 90, 052905 (2007).

    Article  Google Scholar 

  16. Shimotani, H. et al. Insulator-to-metal transition in ZnO by electric double layer gating. Appl. Phys. Lett. 91, 082106 (2007).

    Article  Google Scholar 

  17. Kawasaki, M. et al. Atomic control of the SrTiO3 crystal surface. Science 266, 1540–1542 (1994).

    Article  CAS  Google Scholar 

  18. Tufte, O. N. & Chapman, P. W. Electron mobility in semiconducting strontium titanate. Phys. Rev. 155, 796–802 (1967).

    Article  CAS  Google Scholar 

  19. Shimotani, H., Asanuma, H., Takeya, J. & Iwasa, Y. Electrolyte-gated charge accumulation in organic single crystals. Appl. Phys. Lett. 89, 203501 (2006).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  21. Brinkman, A. et al. Magnetic effects at the interface between non-magnetic oxides. Nature Mater. 6, 493–496 (2007).

    Article  CAS  Google Scholar 

  22. Reyren, N. et al. Superconducting interfaces between insulating oxides. Science 317, 1196–1199 (2007).

    Article  CAS  Google Scholar 

  23. Ando, T., Fowler, A. B. & Stern, F. Electronic properties of two-dimensional systems. Rev. Mod. Phys. 54, 437–672 (1982).

    Article  CAS  Google Scholar 

  24. Neville, R. C., Hoeneisen, B. & Mead, C. A. Permittivity of strontium titanate. J. Appl. Phys. 43, 2124–2131 (1972).

    Article  CAS  Google Scholar 

  25. Mattheiss, L. F. Energy bands for KNiF3, SrTiO3, KMoO3, and KTaO3 . Phys. Rev. B. 6, 4718–4740 (1972).

    Article  CAS  Google Scholar 

  26. Uwe, H., Yoshizaki, R., Sakudo, T., Izumi, A. & Uzumaki, T. Conduction band structure of SrTiO3 . Jpn. J. Appl. Phys. 24 (suppl. 24-2), 335–337 (1985).

    Article  CAS  Google Scholar 

  27. Frederikse, H. P. R., Hosler, W. R., Thurber, W. R., Babiskin, J. & Siebenmann, P. G. Shubnikov–de Haas effect in SrTiO3 . Phys. Rev. 158, 775–778 (1967).

    Article  CAS  Google Scholar 

  28. Herranz, G. et al. Full oxide heterostructure combining a high-TC diluted ferromagnet with a high-mobility conductor. Phys. Rev. B 73, 64403 (2006).

    Article  Google Scholar 

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Acknowledgements

We thank S. Maekawa, M. Mori, N. Reyren, J.-M. Triscone and A. Tsukazaki for fruitful discussions.

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Correspondence to K. Ueno or M. Kawasaki.

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Ueno, K., Nakamura, S., Shimotani, H. et al. Electric-field-induced superconductivity in an insulator. Nature Mater 7, 855–858 (2008). https://doi.org/10.1038/nmat2298

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