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.
Subscribe to Journal
Get full journal access for 1 year
only $17.42 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
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).
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).
Ohtomo, A. & Hwang, H. Y. A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423–426 (2006).
Ohtomo, A. & Hwang, H. Y. Corrigendum: A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 441, 120 (2006).
Huijben, M. et al. Electronically coupled complementary interfaces between perovskite band insulators. Nature Mater. 5, 556–560 (2006).
Hotta, Y., Susaki, T. & Hwang, H. Y. Polar discontinuity doping of the LaVO3/SrTiO3 interface. Phys. Rev. Lett. 99, 236805 (2007).
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).
Okamoto, S., Millis, A. J. & Spaldin, N. A. Lattice relaxation in oxide heterostructures: LaTiO3/SrTiO3 superlattices. Phys. Rev. Lett. 97, 056802 (2006).
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).
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).
Ahn, C. H., Triscone, J.-M. & Mannhart, J. Electric field effect in correlated oxide systems. Nature 424, 1015–1018 (2003).
Reyren, N. et al. Superconducting interfaces between insulating oxides. Science 317, 1196–1199 (2007).
Haeni, J. H. et al. Room-temperature ferroelectricity in strained SrTiO3 . Nature 430, 758–761 (2004).
Brinkman, A. et al. Magnetic effects at the interface between non-magnetic oxides. Nature Mater. 6, 493–496 (2007).
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).
Levi, B. G. Interface between nonmagnetic insulators may be ferromagnetic and conducting. Phys. Today 60, 23–27 (2007).
Eckstein, J. N. Oxide interfaces: Watch out for the lack of oxygen. Nature Mater. 6, 473–474 (2007).
Schooley, J. F., Hosler, W. R. & Cohen, M. L. Superconductivity in semiconducting SrTiO3 . Phys. Rev. Lett. 12, 474–475 (1964).
Siemons, W. et al. Origin of charge density at LaAlO3 on SrTiO3 heterointerfaces: Possibility of intrinsic doping. Phys. Rev. Lett. 98, 196802 (2007).
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).
Herranz, G. et al. High mobility in LaAlO3/SrTiO3 heterostructures: Origin, dimensionality, and perspectives. Phys. Rev. Lett. 98, 216803 (2007).
Ahn, C. H. et al. Local, nonvolatile electronic writing of epitaxial Pb(Zr0.52Ti0.48)O3/SrRuO3 heterostructures. Science 276, 1100–1103 (1997).
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).
Li, H. et al. Two-dimensional growth of high-quality strontium titanate thin films on Si. J. Appl. Phys. 93, 4521–4525 (2003).
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
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).
Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).
Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).
Nakagawa, N., Hwang, H. Y. & Muller, D. A. Why some interfaces cannot be sharp. Nature Mater. 5, 204–209 (2006).
Jenkins, S. J. Ternary half-metallics and related binary compounds: Stoichiometry, surface states, and spin. Phys. Rev. B 70, 245401 (2004).
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).
About this article
Cite this article
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
Nature Materials (2020)
Revealing the Photocharge-Transfer Mechanism at Manganite-Buffered LaAlO3/SrTiO3 Interfaces by Giant Photoresponse
ACS Applied Materials & Interfaces (2020)
Visualizing Charge Transport and Nanoscale Electrochemistry by Hyperspectral Kelvin Probe Force Microscopy
ACS Applied Materials & Interfaces (2020)
Inevitable high density of oxygen vacancies at the surface of polar–nonpolar perovskite heterostructures LaAlO3/SrTiO3
Journal of Applied Physics (2020)
Journal of Semiconductors (2020)