Switchable Induced Polarization in LaAlO3/SrTiO3 Heterostructures

C. W. Bark, P. Sharma, Y. Wang, S. H. Baek, S. Lee, S. Ryu, C. M. Folkman, T. R. Paudel, A. Kumar, S. V. Kalinin, A. Sokolov, E. Y. Tsymbal, M. S. Rzchowski, A. Gruverman, C. B. Eom

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Demonstration of a tunable conductivity of the LaAlO 3/SrTiO 3 interfaces drew significant attention to the development of oxide electronic structures where electronic confinement can be reduced to the nanometer range. While the mechanisms for the conductivity modulation are quite different and include metal-insulator phase transition and surface charge writing, generally it is implied that this effect is a result of electrical modification of the LaAlO 3 surface (either due to electrochemical dissociation of surface adsorbates or free charge deposition) leading to the change in the two-dimensional electron gas (2DEG) density at the LaAlO 3/SrTiO 3 (LAO/STO) interface. In this paper, using piezoresponse force microscopy we demonstrate a switchable electromechanical response of the LAO overlayer, which we attribute to the motion of oxygen vacancies through the LAO layer thickness. These electrically induced reversible changes in bulk stoichiometry of the LAO layer are a signature of a possible additional mechanism for nanoscale oxide 2DEG control on LAO/STO interfaces.

Original languageEnglish
Pages (from-to)1765-1771
Number of pages7
JournalNano Letters
Issue number4
Publication statusPublished - 11 Apr 2012
Externally publishedYes


  • complex oxides
  • Heterointerfaces
  • oxygen vacancies
  • piezoresponse force microscopy


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