Tunable conductivity threshold at polar oxide interfaces

[en] The physical mechanisms responsible for the formation of a two-dimensional electron gas at the interface between insulating SrTiO3 and LaAlO3 have remained a contentious subject since its discovery in 2004. Opinion is divided between an intrinsic mechanism involving the build-up of an internal electric potential due to the polar discontinuity at the interface between SrTiO3 and LaAlO3, and extrinsic mechanisms attributed to structural imperfections. Here we show that interface conductivity is also exhibited when the LaAlO3 layer is diluted with SrTiO3, and that the threshold thickness required to show conductivity scales inversely with the fraction of LaAlO3 in this solid solution, and thereby also with the layer’s formal polarization. These results can be best described in terms of the intrinsic polar-catastrophe model, hence providing the most compelling evidence, to date, in favour of this mechanism.

Disciplines :

Physics

Author, co-author :

Reinle-Schmitt, M.L.

Cancellieri, C.

Li, D.

Fontaine, Denis ; Université de Liège - ULiège > Département de physique > Physique théorique des matériaux

Medarde, M.

Pomjakushina, E.

Schneider, C.W.

Gariglio, S.

Ghosez, Philippe ; Université de Liège - ULiège > Département de physique > Physique théorique des matériaux

Triscone, J.-M.

Willmott, P.R.

Language :

English

Title :

Tunable conductivity threshold at polar oxide interfaces

Publication date :

03 July 2012

Journal title :

Nature Communications

eISSN :

2041-1723

Publisher :

Nature Publishing Group, London, United Kingdom

Volume :

Pages :

932

Peer reviewed :

Peer Reviewed verified by ORBi

Tags :

Tier-1 supercomputer
CÉCI : Consortium des Équipements de Calcul Intensif

Available on ORBi :

since 04 July 2012

Statistics

Number of views

91 (24 by ULiège)

Number of downloads

2 (0 by ULiège)

More statistics

Scopus citations^®

120

Scopus citations^®
without self-citations

105

OpenCitations

110

Bibliography

Okamoto, S. & Millis, A. J. Electronic reconstruction at an interface between a Mott insulator and a band insulator. Nature 428, 630-633 (2004). (Pubitemid 38524800)
Ohtomo, A. & Hwang, H. Y. A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423-426 (2004). (Pubitemid 38168490)
Gozar, A. et al. High-Temperature interface superconductivity between metallic and insulating copper oxides. Nature 455, 782-785 (2008).
Zubko, P., Gariglio, S., Gabay, M., Ghosez, P. & Triscone, J.-M. Interface physics in complex oxide heterostructures. Annu. Rev. Condens. Matter Phys. 2, 141-165 (2011).
Hwang, H. Y. et al. Emergent phenomena at oxide interfaces. Nat. Mater. 11, 103-113 (2012).
Nakagawa, N., Hwang, H. Y. & Muller, D. A. Why some interfaces cannot be sharp. Nat. Mater. 5, 204-209 (2006). (Pubitemid 43320635)
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). (Pubitemid 44497997)
Schlom, D. G. & Mannhart, J. Oxide electronics: interface takes charge over Si. Nat. Mater. 10, 168-169 (2011).
Huijben, M. et al. Electronically coupled complementary interfaces between perovskite band insulators. Nat. Mater. 5, 556-560 (2006). (Pubitemid 43993078)
Cancellieri, C. et al. Influence of the growth conditions on the LaAlO3/SrTiO3 interface electronic properties. Europhys. Lett. 91, 17004 (2010).
Popovic, Z. S., Satpathy, S. & Martin, R. M. Origin of the two-dimensional electron gas carrier density at the LaAlO3 on SrTiO3 interface. Phys. Rev. Lett. 101, 256801 (2008).
Lee, J. & Demkov, A. A. Charge origin and localization at the n-Type SrTiO3/LaAlO3 interface. Phys. Rev. B 78, 193104 (2008).
Siemons, W. et al. Origin of charge density at LaAlO3 on SrTiO 3 heterointerfaces: Possibility of intrinsic doping. Phys. Rev. Lett. 98, 196802 (2007).
Herranz, G. et al. High mobility in LaAlO3/SrTiO3 heterostructures: Origin, dimensionality and perspectives. Phys. Rev. Lett. 98, 216803 (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(R) (2007).
Bristowe, N. C., Littlewood, P. B. & Artacho, E. Surface defects and conduction in polar oxide heterostructures. Phys. Rev. B 83, 205405 (2011).
Xie, Y., Hikita, Y., Bell, C. & Hwang, H. Y. Control of electronic conduction at an oxide heterointerface using surface polar adsorbates. Nat. Commun. 2, 494 (2011).
Willmott, P. R. et al. Structural basis for the conducting interface between LaAlO3 and SrTiO3. Phys. Rev. Lett. 99, 155502 (2007).
Qiao, L. et al. Thermodynamic instability at the stoichiometric LaAlO3/SrTiO3 (001) interface. J. Phys. Condens. Matter 22, 312201 (2010).
Qiao, L. et al. Epitaxial growth, structure, and intermixing at the LaAlO3/SrTiO3 interface as the film stoichiometry is varied. Phys. Rev. B 83, 085408 (2011).
Segal, Y., Ngai, J. H., Reiner, J. W., Walker, F. J. & Ahn, C. H. X-ray photoemission studies of the metal-insulator transition in LaAlO3/SrTiO3 structures grown by molecular beam epitaxy. Phys. Rev. B 80, 241107 (2009).
Pauli, S. A. et al. Evolution of the interfacial structure of LaAlO3 on SrTiO3. Phys. Rev. Lett. 106, 036101 (2011).
Cancellieri, C. et al. Electrostriction at the LaAlO3/SrTiO3 interface. Phys. Rev. Lett. 107, 056102 (2011).
Stengel, M. & Vanderbilt, D. Berry-phase theory of polar discontinuities at oxide-oxide interfaces. Phys. Rev. B 80, 241103 (2009).
Konaka, T., Sato, M., Asano, H. & Kubo, S. Relative permittivity and dielectric loss tangent of substrate materials for high-Tc superconducting film. J. Superconduct. 4, 283-288 (1991). (Pubitemid 21707580)
Bert, J. A. et al. Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface. Nat. Phys. 7, 767-771 (2011).
Gariglio, S., Reyren, N., Caviglia, A. D. & Triscone, J.-M. Superconductivity at the LaAlO3/SrTiO3 interface. J. Phys. Condens. Matter 21, 164213 (2009).
Stengel, M. & Spaldin, N. A. Origin of the dielectric dead layer in nanoscale capacitors. Nature 443, 679-682 (2006). (Pubitemid 44564708)
Sun, P. H. et al. Dielectric behavior of (1-x)LaAlO3 xSrTiO3 solid solution system at microwave frequencies. Jap. J. Appl. Phys. 37, 5625-5629 (1998).
Chen, Y. et al. Metallic and insulating interfaces of amorphous SrTiO3-based oxide heterostructures. Nano Lett. 11, 3774-3778 (2011).
Bilc, D. I. et al. Hybrid exchange-correlation functional for accurate prediction of the electronic and structural properties of ferroelectric oxides. Phys. Rev. B 77, 165107 (2008).
Wu, Z. & Cohen, R. E. More accurate generalized gradient approximation for solids. Phys. Rev. B 73, 235116 (2006).
Becke, A. D. Density-functional thermochemistry. IV. A new dynamical correlation functional and implications for exact-exchange mixing. J. Chem. Phys. 104, 1040-1046 (1996). (Pubitemid 126747264)
Delugas, P. et al. Spontaneous 2-dimensional carrier confinement at the n-Type SrTiO3/LaAlO3 interface. Phys. Rev. Lett. 106, 166807 (2011).
Dovesi, R. et al. CRYSTAL: a computational tool for the ab initio study of the electronic properties of crystals. Z. Kristallogr. 220, 571-573 (2005). (Pubitemid 40778243)
Bredow, T., Heitjans, P. & Wilkening, M. Electric field gradient calculations for LixTiS2 and comparison with 7Li NMR results. Phys. Rev. B 70, 115111 (2004).
Piskunov, S., Heifets, E., Eglitis, R. I. & Borstel, G. Bulk properties and electronic structure of SrTiO3, BaTiO3, PbTiO3 perovskites: an ab initio HF/DFT study. Comp. Mat. Sci. 29, 165-178 (2004).
Towler, M. CRYSTAL resource page, 2011, see www.tcm.phy.cam.ac.uk/mdt26/ crystal.html.
Cao, X. Y. & Dolg, M. Segmented contraction scheme for small-core lanthanide pseudopotential basis sets. J. Mol. Struct. Theochem. 581, 139-147 (2002).