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

*AcRF Tier 1 Grants No. R-144-000-364-112 and No. R-144-000-390-114, CRP Awards No. NRFCRP15-2015-01 and No. NRF-CRP10-2012-02), Tier 2 Grant (MOE2017-T2-1-129).

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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