Energetic electrons are scattered strongly by matter, delivering a wealth of information about the specimen in the distribution of scattered electrons. This talk will explore some different ways to extract this specimen information from the scattered intensity distribution and will illustrate these with some applications to functional materials.

In a philosophical sense, we will discuss how we might craft the incident electron wave field and manipulate the scattering within the specimen to generate a scattered intensity distribution rich in the particular specimen information we are seeking. The talk will include some specific topics: * Crafting electron wave-fields and their resultant interaction with the specimen[1,2]; * Exploiting dynamical scattering for measuring the phase of crystal structure factors[3,4]; * Symmetry STEM (S-STEM) where we form image contrast from the degree of a chosen symmetry in the distribution of scattered electrons⁵; * Real Space STEM (R-STEM) where we form image contrast by using a selection of scattered electrons recorded in coordinate space, rather than momentum space, as the probe is scanned across the specimen[6-8]; and * Position-resolved cathodoluminescence in the SEM, to identify the position that light is emitted, relative to the point of excitation (the position of the electron beam)⁹.

I will illustrate these approaches with applications to the measurement of structure and electronic structure of functional materials, including plasmonic and semiconducting nanoparticle systems.

A separate talk focussing on applications to functional perovskites (photoactive, colossal magneto-resistive, ferroelectric and ion-conducting) will be given in the Department of Physics on June 13 @ 14:30 Simpkins Lee room of the Beecroft Building.

[1] Zheng CL, Petersen TC, Kirmse H, Neumann W, Morgan MF, Etheridge J Phys Rev Letts 119 17 174801 (2017)
[2] Nguyen DT, Findlay SD, Etheridge J Ultramicroscopy 184 143–155 (2018)
[3] Nakashima, PH, Moodie, AF, Etheridge, J PNAS 110 14144-14149 (2013)
[4] Guo Y, Nakashima P, Etheridge J IUCrJ 5 753-764 (2018)
[5] Krajnak M, Etheridge J, PNAS 117 27805-27810 (2020)
[6] Etheridge J, Lazar, S, Dwyer C, Botton, G, Phys Rev Letts 106 160802 (2011)
[7] Dwyer C, Lazar S, Chang LY, Etheridge J, Acta Cryst. A68 196 (2012)
[8] Zheng CL, Zhu Y, Lazar S, Etheridge J, Phys Rev Letts 112 166101 (2014)
[9] Liu A, Davis T, Coenen T, Hari S, Voortman L, Xu Z, Yuan G, Ballard P, Funston A, Etheridge J Small 2207747 (2023)

Short biography:
Joanne Etheridge is the founding Director of the Monash Centre for Electron Microscopy and the Australian Research Council Georgina Sweet Laureate Fellow in the School of Physics and Astronomy at Monash University. She obtained a degree and PhD in physics from the University of Melbourne and RMIT University, respectively, before appointments at the University of Cambridge in the Department of Materials Science and Metallurgy and Newnham College, including a Rosalind Franklin Research Fellowship and a Royal Society University Research Fellowship.

Professor Etheridge returned to Melbourne to join Monash University where she established the Monash Centre for Electron Microscopy. She conducts research in the theory and development of new electron scattering methods for determining the atomic and electronic structure of condensed matter. Professor Etheridge also applies these methods to the study of structure-property relationships in functional materials.

Professor Etheridge is a Fellow of the Australian Academy of Science.