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Nanoscale control of an interfacial metal–insulator transition at room temperature

Abstract

Experimental1,2,3,4,5,6,7 and theoretical8,9 investigations have demonstrated that a quasi-two-dimensional electron gas (q-2DEG) can form at the interface between two insulators: non-polar SrTiO3 and polar LaTiO3 (ref. 2), LaAlO3 (refs 3–5), KTaO3 (ref. 7) or LaVO3 (ref. 6). Electronically, the situation is analogous to the q-2DEGs formed in semiconductor heterostructures by modulation doping. LaAlO3/SrTiO3 heterostructures have recently been shown10 to exhibit a hysteretic electric-field-induced metal–insulator quantum phase transition for LaAlO3 thicknesses of 3 unit cells. Here, we report the creation and erasure of nanoscale conducting regions at the interface between two insulating oxides, LaAlO3 and SrTiO3. Using voltages applied by a conducting atomic force microscope (AFM) probe, the buried LaAlO3/SrTiO3 interface is locally and reversibly switched between insulating and conducting states. Persistent field effects are observed using the AFM probe as a gate. Patterning of conducting lines with widths of 3 nm, as well as arrays of conducting islands with densities >1014 inch−2, is demonstrated. The patterned structures are stable for >24 h at room temperature.

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Figure 1: Writing and erasing nanowires at the LaAlO3/SrTiO3 interface.
Figure 2: Current–voltage characteristics of LaAlO3/SrTiO3 interface.
Figure 3: Measuring the limits of conducting island density.
Figure 4: Calculated LDOS of LaAlO3/SrTiO3 for ‘ideal’ and reduced LaAlO3 surfaces for each layer in the 3 unit cell LaAlO3 film and for the first four unit cells of the SrTiO3 substrate.

References

  1. Schneider, C. W., Thiel, S., Hammerl, G., Richter, C. & Mannhart, J. Microlithography of electron gases formed at interfaces in oxide heterostructures. Appl. Phys. Lett. 89, 122101 (2006).

    Article  Google Scholar 

  2. Ohtomo, A., Muller, D. A., Grazul, J. L. & Hwang, H. Y. Artificial charge-modulation in atomic-scale perovskite titanate superlattices. Nature 419, 378–380 (2002).

    Article  CAS  Google Scholar 

  3. Ohtomo, A. & Hwang, H. Y. A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423–426 (2006).

    Article  Google Scholar 

  4. Ohtomo, A. & Hwang, H. Y. Corrigendum: A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 441, 120 (2006).

    Article  CAS  Google Scholar 

  5. Huijben, M. et al. Electronically coupled complementary interfaces between perovskite band insulators. Nature Mater. 5, 556–560 (2006).

    Article  CAS  Google Scholar 

  6. Hotta, Y., Susaki, T. & Hwang, H. Y. Polar discontinuity doping of the LaVO3/SrTiO3 interface. Phys. Rev. Lett. 99, 236805 (2007).

    Article  CAS  Google Scholar 

  7. Kalabukhov, A., Gunnarsson, R., Claeson, T. & Winkler, D. Electrical transport properties of polar heterointerface between KTaO3 and SrTiO3. Preprint at <http://arxiv.org/abs/cond-mat/0704.1050> (2007).

  8. Okamoto, S., Millis, A. J. & Spaldin, N. A. Lattice relaxation in oxide heterostructures: LaTiO3/SrTiO3 superlattices. Phys. Rev. Lett. 97, 056802 (2006).

    Article  Google Scholar 

  9. Pentcheva, R. & Pickett, W. E. Charge localization or itineracy at LaAlO3/SrTiO3 interfaces: Hole polarons, oxygen vacancies, and mobile electrons. Phys. Rev. B 74, 035112 (2006).

    Article  Google Scholar 

  10. 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).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  13. Haeni, J. H. et al. Room-temperature ferroelectricity in strained SrTiO3 . Nature 430, 758–761 (2004).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  15. Helmolt, R. v., Wecker, J., Holzapfel, B., Schultz, L. & Samwer, K. Giant negative magnetoresistance in perovskite like La2/3Ba1/3MnOx ferromagnetic films. Phys. Rev. Lett. 71, 2331–2333 (1993).

    Article  Google Scholar 

  16. Levi, B. G. Interface between nonmagnetic insulators may be ferromagnetic and conducting. Phys. Today 60, 23–27 (2007).

    Article  Google Scholar 

  17. Eckstein, J. N. Oxide interfaces: Watch out for the lack of oxygen. Nature Mater. 6, 473–474 (2007).

    Article  CAS  Google Scholar 

  18. Schooley, J. F., Hosler, W. R. & Cohen, M. L. Superconductivity in semiconducting SrTiO3 . Phys. Rev. Lett. 12, 474–475 (1964).

    Article  CAS  Google Scholar 

  19. Siemons, W. et al. Origin of charge density at LaAlO3 on SrTiO3 heterointerfaces: Possibility of intrinsic doping. Phys. Rev. Lett. 98, 196802 (2007).

    Article  Google Scholar 

  20. Kalabukhov, A. et al. Effect of oxygen vacancies in the SrTiO3 substrate on the electrical properties of the LaAlO3/SrTiO3 interface. Phys. Rev. B 75, 121404 (2007).

    Article  Google Scholar 

  21. Herranz, G. et al. High mobility in LaAlO3/SrTiO3 heterostructures: Origin, dimensionality, and perspectives. Phys. Rev. Lett. 98, 216803 (2007).

    Article  CAS  Google Scholar 

  22. Ahn, C. H. et al. Local, nonvolatile electronic writing of epitaxial Pb(Zr0.52Ti0.48)O3/SrRuO3 heterostructures. Science 276, 1100–1103 (1997).

    Article  CAS  Google Scholar 

  23. Frammelsberger, W., Benstetter, G., Kiely, J. & Stamp, R. C-AFM-based thickness determination of thin and ultra-thin SiO2 films by use of different conductive-coated probe tips. Appl. Surf. Sci. 253, 3615–3626 (2007).

    Article  CAS  Google Scholar 

  24. Li, H. et al. Two-dimensional growth of high-quality strontium titanate thin films on Si. J. Appl. Phys. 93, 4521–4525 (2003).

    Article  CAS  Google Scholar 

  25. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

    Article  CAS  Google Scholar 

  26. Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).

    Article  CAS  Google Scholar 

  27. Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).

    Article  CAS  Google Scholar 

  28. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

    Article  Google Scholar 

  29. Nakagawa, N., Hwang, H. Y. & Muller, D. A. Why some interfaces cannot be sharp. Nature Mater. 5, 204–209 (2006).

    Article  CAS  Google Scholar 

  30. Jenkins, S. J. Ternary half-metallics and related binary compounds: Stoichiometry, surface states, and spin. Phys. Rev. B 70, 245401 (2004).

    Article  Google Scholar 

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Acknowledgements

We gratefully acknowledge helpful interactions and discussions with T. Kopp and S. K. Streiffer. Computations were carried out at the DoD Major Shared Resource Centers. This work was supported by DARPA DAAD-19-01-1-0650, NSF DMR-0704022, the DFG (SFB 484), the EC (Nanoxide) and the ESF (THIOX).

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Correspondence to J. Levy.

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Cen, C., Thiel, S., Hammerl, G. et al. Nanoscale control of an interfacial metal–insulator transition at room temperature. Nature Mater 7, 298–302 (2008). https://doi.org/10.1038/nmat2136

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