PhD position: Precise atomic-scale structure determination in thick nanostructures

Monash University, Australia

Updated: about 1 year ago
Deadline: The position may have been removed or expired!

Knowing where atoms are and how they are bonded is vital to understand the properties and performance of advanced materials. Among various atomic-scale characterisation methods, transmission electron microscopy has proven highly successful for precise structure determination. Breakthrough advances in fast-readout pixel detectors are enabling structure determination at unprecedented resolution. Despite these new tools, reliable structure determination remains restricted to ultrathin (a few nanometers thick) materials – a small subset of all materials of technological interest – as existing methods fail in thicker nanostructures due to multiple scattering of the probe electrons. Overcoming this limitation is the focus of much research [1-3].

This computational project could take several directions, including:

  • Extending existing thin-object reconstruction strategies by developing iterative algorithms to correct for multiple scattering.
  • Comparing phase retrieval strategies for determining the so-called scattering matrix with as few measurements as possible.
  • Developing methods to characterise instrument aberrations from the data itself.
  • Generalising methods to handle non-periodic structures.

References

[1] D. Ren, M. Chen, L. Waller & C. Ophus, ArXiv eprints (2018), arXiv:1807.03886

[2] H.G. Brown et al., Physical Review Letters 121 (2018) 266102

F. Wang, R.S. Pennington & C.T. Koch, Physical Review Letters 117 (2016) 015501

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