Intertwining ferroelectricity and two-dimensional electron gas at oxide interfaces

POSTER

Abstract

We report the coexistence of ferroelectricity and two-dimensional electron gas (2DEG) in ferroelectric BaxSr1-xTiO3 (BST) thin films at the LaAlO3/BaxSr1-xTiO3 (LAO/BST) interface using piezoresponse force microscopy (PFM), electrical and optical measurements, scanning transmission electron microscopy (STEM) as well as first-principles calculations. The 2DEG is introduced into ferroelectric BST thin films by the polar discontinuity at LAO/BST interface similar to that of LAO/STO. The ferroelectricity of BST thin film of ~3.2 nm is found to persist with a two-dimensional carrier density of ~0.05 electron per unit cell. Our results demonstrate the coexistence of ferroelectricity and two-dimensional electron gas, which are conventionally regarded as mutually exclusive, in oxide heterostructures.

In collaboration with: S. W. Zeng, C. J. Li, R. Guo, J. X. Xiao, Z. Huang, W. M. Lv, K. Han, P. Yang, C. G. Li, Z. S. Lim, H. Wang, Y. Zhang, S. J. Chua, K. Y. Zeng

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Presenters

  • Ariando Ariando

    Department of Physics & NUSNNI-NanoCore, Natl Univ of Singapore, Department of Physics, National University of Singapore, Natl Univ of Singapore

Authors

  • Ariando Ariando

    Department of Physics & NUSNNI-NanoCore, Natl Univ of Singapore, Department of Physics, National University of Singapore, Natl Univ of Singapore

  • W. X. Zhou

    Department of Physics & NUSNNI-NanoCore, Natl Univ of Singapore

  • H. J. Wu

    Department of MSE, National University of Singapore

  • J. Zhou

    Department of Physics & NUSNNI-NanoCore, Natl Univ of Singapore

  • Thirumalai Venkatesan

    Department of Physics & NUSNNI-NanoCore, Natl Univ of Singapore, Department of Physics, National University of Singapore, NUSNNI, National University of Singapore, Natl Univ of Singapore, Nanoscience and Nanotechnology Institute, National University of Singapore, National University of Singapore

  • J. S. Chen

    Department of MSE, National University of Singapore

  • Yuan Feng

    Physics, Natl Univ of Singapore, Department of Physics & NUSNNI-NanoCore, Natl Univ of Singapore, Department of Physics, National University of Singapore

  • S. J. Pennycook

    Department of MSE, National University of Singapore