Enhanced transition temperature due to tetragonal domains in two-dimensional superconducting strontium titanate

ORAL

Abstract

Strontium titanate (SrTiO$_3$) is a key component in superconducting heterostructures such as LaAlO$_3$/SrTiO$_3$ and monolayer FeSe on SrTiO$_3$, yet superconductivity in bare SrTiO$_3$ is not fully understood. We used a scanning superconducting quantum interference device susceptometer to image the diamagnetic response as a function of temperature in samples of SrTiO$_3$ containing either a 5.5 nm or a 36.9 nm-thick slab of niobium-doped SrTiO$_3$. We find that stripe-like regions remain superconducting at higher temperatures than the rest of the sample. The shape and orientation of the features, as well as their behavior in a subsequent cooldown, are consistent with an origin in the low-temperature tetragonal domain structure of SrTiO$_3$. These results suggest a variety of mechanisms by which the transition temperature could be enhanced and may help constrain theories of superconductivity in SrTiO$_3$.

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Authors

  • Hilary Noad

    • SIMES, SLAC National Accelerator Laboratory; Department of Applied Physics, Stanford University

  • Katja Nowack

    • Department of Applied Physics, Stanford University

  • Eric Spanton

    • SIMES, SLAC National Accelerator Laboratory; Department of Physics, Stanford University

  • Hisashi Inoue

    • Department of Applied Physics, Stanford University

  • Minu Kim

    • SIMES, SLAC National Accelerator Laboratory

  • Chris Bell

    • SIMES, SLAC National Accelerator Laboratory

  • Yasuyuki Hikita

    • SIMES, SLAC National Accelerator Laboratory

  • Harold Y. Hwang

    • SIMES, SLAC National Accelerator Laboratory; Department of Applied Physics, Stanford University

  • Kathryn Moler

    • SIMES, SLAC National Accelerator Laboratory; Departments of Physics and Applied Physics, Stanford University