Enhancement of Young's modulus in freestanding SrTiO3 thin films

ORAL

Abstract

Recent developments in thin fil growth provide a powerful route to free-standing single-crystal films of perovskite oxides by water etching of a sacrificial underlayer (Di Lu et al., Nature Materials 15, 1255 (2016)). We have used atomic force microscopy to systematically probe the elastic properties of suspended SrTiO3 films, in a thickness series from 4-98 nm, which has been previously inaccessible and unexplored. We observe the thickness dependence of elastic modulus of SrTiO3 to be non-monotonic, with a strong enhancement of stiffness for thicknesses below 30 nm. We provide evidence that the nature of this elastic stiffening lies in an effective flexoelectric coupling. This study provides the basis for studying strain manipulation and strain control of oxides at the nanoscale. In particular, oxide membranes can be designed to mimic stiffnesses of 2d materials like graphene and transition metal dichalcogenides.

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Presenters

  • Varun Harbola

    Physics, Stanford University

Authors

  • Varun Harbola

    Physics, Stanford University

  • Samuel Crossley

    Applied Physics, Stanford University

  • Seung Sae Hong

    Applied Physics, Stanford University

  • Yorick Birkholzer

    Institute for nanotechnology, University of Twente

  • Di Lu

    Physics, Stanford University

  • Yasuyuki Hikita

    Stanford Institute for Material and Energy Sciences, SLAC National Accelerator Laboratory, SIMES, SLAC National Accelerator Lab, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory

  • Harold Hwang

    Applied Physics, Stanford University, SIMES, SLAC National Accelerator Lab, Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University