Se diffusion into SrTiO<sub>3</sub> substrate in monolayer FeSe/SrTiO<sub>3</sub>

ORAL

Abstract

Monolayer FeSe on a SrTiO3 (STO) substrate is a high-temperature superconductor with reported Tc as high as 100 K, but the mechanism for such enhanced Tc remains poorly understood. Here we characterize the atomic structural and chemical composition of the FeSe/STO interface using transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Our measurements reveal the presence of selenium in the top layers of STO, located on interstitial sites and in the TiO2 layers. We support our measurement with density functional theory (DFT) calculations. We discuss implications of our findings on substrate-induced electron doping in the FeSe/STO heterostructure.

*This work is supported by the Gordon and Betty Moore Foundation’s EPiQS Initiative, grant GBMF4536; Office of Naval Research, Grant N00014-18-1-2691, and Swiss National Science Foundation, grant P400P2_183890 and was performed in part at the Center for Nanoscale Systems (CNS), a hub of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959. CNS is part of Harvard University.

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Presenters

  • Samantha O'Sullivan

    • Harvard University

Authors

  • Samantha O'Sullivan

    • Harvard University

  • Ruizhe Kang

    • Harvard University

  • Jules Gardener

    • Harvard University

  • Austin Akey

    • Harvard University
    • Center for Nanoscale Systems, Harvard University

  • Christian E. Matt

    • Harvard University

  • Jenny E. Hoffman

    • Harvard University
    • Department of Physics, Harvard University