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High-temperature interface superconductivity between metallic and insulating copper oxides

Nature volume 455, pages 782–785 (2008)Cite this article

Abstract

The realization of high-transition-temperature (high-Tc) superconductivity confined to nanometre-sized interfaces has been a long-standing goal because of potential applications1,2 and the opportunity to study quantum phenomena in reduced dimensions3,4. This has been, however, a challenging target: in conventional metals, the high electron density restricts interface effects (such as carrier depletion or accumulation) to a region much narrower than the coherence length, which is the scale necessary for superconductivity to occur. By contrast, in copper oxides the carrier density is low whereas Tc is high and the coherence length very short, which provides an opportunity—but at a price: the interface must be atomically perfect. Here we report superconductivity in bilayers consisting of an insulator (La2CuO4) and a metal (La1.55Sr0.45CuO4), neither of which is superconducting in isolation. In these bilayers, Tc is either ∼15 K or ∼30 K, depending on the layering sequence. This highly robust phenomenon is confined within 2–3 nm of the interface. If such a bilayer is exposed to ozone, Tc exceeds 50 K, and this enhanced superconductivity is also shown to originate from an interface layer about 1–2 unit cells thick. Enhancement of Tc in bilayer systems was observed previously5 but the essential role of the interface was not recognized at the time.

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Figure 1: The dependence of resistance on temperature for single-phase and bilayer films.
Figure 2: The dependence on the layer thickness.
Figure 3: Nonlinear screening effects in a single-phase S film and an M–S bilayer.
Figure 4: Analysis of an M–I bilayer by scanning transmission electron microscopy and electron energy-loss spectroscopy.

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References

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

    Article  ADS  CAS  Google Scholar 

  2. Ahn, C. H. et al. Electrostatic modulation of superconductivity in ultrathin GdBa2Cu3O7-δ . Science 284, 1152–1155 (1999)

    Article  ADS  CAS  Google Scholar 

  3. Berezinskii, V. L. Destruction of long-range order in one-dimensional and 2-dimensional systems having a continuous symmetry group 2. Quantum systems. Sov. Phys. JETP 34, 610–616 (1972)

    ADS  Google Scholar 

  4. Kosterlitz, J. M. & Thouless, D. J. Ordering, metastability and phase transitions in two-dimensional systems. J. Phys. C 6, 1181–1203 (1973)

    Article  ADS  CAS  Google Scholar 

  5. Bozovic, I., Logvenov, G., Belca, I., Narimbetov, B. & Sveklo, I. Epitaxial strain and superconductivity in La2-xSrxCuO4 thin films. Phys. Rev. Lett. 89, 107001 (2002)

    Article  ADS  CAS  Google Scholar 

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

    Article  ADS  CAS  Google Scholar 

  7. Seguchi, Y., Tsuboi, T. & Suzuki, T. Magnetic-field-enhanced superconductivity in Au/Ge layered films. J. Phys. Soc. Jpn 61, 1875–1878 (1992)

    Article  ADS  CAS  Google Scholar 

  8. Fogel, N. Ya. et al. Interfacial superconductivity in semiconducting monochalcogenide superlattices. Phys. Rev. B 73, R161306 (2006)

    Article  ADS  Google Scholar 

  9. Kastner, M. A. & Birgeneau, R. J. Magnetic, transport and optical properties of monolayer copper oxides. Rev. Mod. Phys. 70, 897–928 (1998)

    Article  ADS  CAS  Google Scholar 

  10. Bozovic, I. Atomic layer engineering of superconducting oxides: Yesterday, today, tomorrow. IEEE Trans. Appl. Supercond. 11, 2686–2695 (2001)

    Article  ADS  Google Scholar 

  11. Bozovic, I., Eckstein, J. N. & Virshup, G. F. Superconducting oxide multilayers and superlattices: Physics, chemistry and nanoengineering. Physica C 235–240, 178–181 (1994)

    Article  ADS  Google Scholar 

  12. Bozovic, I. et al. No mixing of superconductivity and antiferromagnetism in a high temperature superconductor. Nature 422, 873–875 (2003)

    Article  ADS  CAS  Google Scholar 

  13. Gozar, A., Logvenov, G., Butko, V. B. & Bozovic, I. Surface structure analysis of atomically smooth BaBiO3 films. Phys. Rev. B 75, R201402 (2007)

    Article  ADS  Google Scholar 

  14. Sato, H., Tsukada, A., Naito, M. & Matsuda, A. La2-xSrxCuOy epitaxial films (x = 0 to 2): Structure, strain, and superconductivity. Phys. Rev. B 61, 12447–12456 (2000)

    Article  ADS  CAS  Google Scholar 

  15. Locquet, J.-P. et al. Doubling the critical temperature of La1. 9Sr0. 1CuO4 using epitaxial strain. Nature 394, 453–456 (1998)

    Article  ADS  CAS  Google Scholar 

  16. Hebard, A. F. & Fiory, A. T. Evidence for the Kosterlitz-Thouless transition in thin superconducting aluminum films. Phys. Rev. Lett. 44, 291–294 (1980)

    Article  ADS  CAS  Google Scholar 

  17. Claassen, J. H., Reeves, M. E. & Soulen, R. J. A contactless method for measurement of the critical current density and critical temperature of superconducting rings. Rev. Sci. Instrum. 62, 996–1004 (1991)

    Article  ADS  CAS  Google Scholar 

  18. Clem, J. R. & Coffey, M. W. Vortex dynamics in a type-II superconducting film and complex linear-response functions. Phys. Rev. B 46, 14662–14674 (1992)

    Article  CAS  Google Scholar 

  19. Jensen, H. J. & Minnhagen, P. Two-dimensional vortex fluctuations in the nonlinear current-voltage characteristics for high-temperature superconductors. Phys. Rev. Lett. 66, 1630–1633 (1991)

    Article  ADS  CAS  Google Scholar 

  20. de Vries, J. W. C., Stollman, G. M. & Gijs, M. A. M. Analysis of the critical current density in high-Tc superconducting films. Physica C 157, 406–414 (1989)

    Article  ADS  CAS  Google Scholar 

  21. Smadici, S. et al. Hole delocalization in superconducting La2CuO4-La1. 64Sr0. 36CuO4 superlattices. Preprint at 〈http://xxx.lanl.gov/abs/0805.3189〉 (2008)

  22. Ino, A. et al. Chemical potential shift in overdoped and underdoped La2-xSrxCuO4 . Phys. Rev. Lett. 79, 2101–2104 (1997)

    Article  ADS  CAS  Google Scholar 

  23. Fujita, K., Noda, T., Kojima, K. M., Eisaki, H. & Uchida, S. Effect of disorder outside the CuO2 planes on Tc of copper oxide superconductors. Phys. Rev. Lett. 95, 097006 (2005)

    Article  ADS  CAS  Google Scholar 

  24. Ginzburg, V. L. On interface superconductivity. Phys. Lett. 13, 101–102 (1964)

    Article  ADS  CAS  Google Scholar 

  25. Kivelson, S. A. Making high Tc higher: A theoretical proposal. Physica B 318, 61–67 (2002)

    Article  ADS  CAS  Google Scholar 

  26. Romberg, H., Alexander, M., Nücker, N., Adelmann, P. & Fink, J. Electronic structure of the system La2-xSrxCuO4+δ . Phys. Rev. B 42, R8768–R8771 (1990)

    Article  ADS  Google Scholar 

  27. Chen, C. T. et al. Electronic states in La2-xSrxCuO4+δ probed by soft-x-ray absorption. Phys. Rev. Lett. 66, 104–107 (1991)

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

The work at BNL was supported by US DOE. L.F.K. and D.A.M. acknowledge support under the ONR EMMA MURI and by the Cornell Center for Materials Research. L.F.K. acknowledges financial support by Applied Materials.

Author Contributions A.G. and G.L. contributed equally to this work. Film synthesis and characterization was by G.L and I.B.; transport and time-of-flight ion scattering and recoil spectroscopy was by A.G.; lithography was by A.T.B.; electron microscopy was by L.F.K. and supervised by D.A.M.; and TEM sample preparation was by L.A.G. and L.F.K.

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Authors and Affiliations

  1. Brookhaven National Laboratory, Upton, New York 11973-5000, USA ,

    A. Gozar, G. Logvenov, A. T. Bollinger & I. Bozovic

  2. School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA ,

    L. Fitting Kourkoutis & D. A. Muller

  3. FEI Company, Hillsboro, Oregon 97124, USA ,

    L. A. Giannuzzi

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  1. A. Gozar
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  2. G. Logvenov
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  5. L. A. Giannuzzi
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  6. D. A. Muller
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  7. I. Bozovic
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Correspondence to I. Bozovic.

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Gozar, A., Logvenov, G., Kourkoutis, L. et al. High-temperature interface superconductivity between metallic and insulating copper oxides. Nature 455, 782–785 (2008). https://doi.org/10.1038/nature07293

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