Peer-reviewed publications

N. Y. Kim*, H. Zhong*, J. Zhang*, C. M. O’Leary*, Y. Liao, J. Zou, H. Sha, M. Pham, W. Li, Y. Yuan, J.-H. Park, D. Kim, H. Jiang, J. Kong, M. Chi and J. Miao, “Three-dimensional imaging of individual carbon atoms”, Nature Nanotechnology, in press, 2026. (Link to preprint)
J. A. Chalmers, M. Ourgessa, S. F. Ausman, C. O’Leary, A. Khan, J. J. Kas, S. R. Bare, F. D. Vila and S. L. Scott, “Rapid Migration of Oxide-Supported Ga(I) Ions, and Consequences for Catalytic Propane Dehydrogenation”, ACS Catalysis, vol. 16, no. 18, pp. 18016–18027, 2026. (Link to article)
M. J. Zachman, H. Hafiz, C. M. O’Leary, C. Lim, D. Y. Chung, S. Li, S. Park, J. Kim, D. A. Cullen, E. F. Holby and V. R. Stamenkovic, “Insights into Native Single-Atom Electrocatalyst Site Structures”, ACS Nano, vol. 20, no. 24, pp. 17490–17500, 2026. (Link to article)
Y. Liao, H. Sha, C. M. O’Leary, H. Zhong, Y. Yang and J. Miao, “Accurate determination of the 3D atomic structure of amorphous materials”, Nature, vol. 649, pp. 1123–1129, 2026. (Link to article)
C. M. O’Leary*, H. Sha*, J. Zhang*, C. Su, S. Kahn, H. Jiang, A. Zettl, J. Ciston and J. Miao, “Three-dimensional structure of buried heterointerfaces revealed by multislice ptychography”, Physical Review Applied, vol. 22, p. 014016, 2024. (Link to article)
D. J. Chang*, C. M. O'Leary*, C. Su, D. A. Jacobs, S. Kahn, A. Zettl, J. Ciston, P. Ercius and J. Miao, “Deep-Learning Electron Diffractive Imaging”, Physical Review Letters, vol. 130, p. 016101, 2023. (Link to article)
A. Rana, C.-T. Liao, E. Iacocca, J. Zou, M. Pham, X. Lu, E.-E. Cating Subramanian, Y. H. Lo, S. A. Ryan, C. S. Bevis, R. M. Karl Jr, A. J. Glaid, J. Rable, P. Mahale, J. Hirst, T. Ostler, W. Liu, C. M. O’Leary, Y.-S. Yu, K. Bustillo, H. Ohldag, D. A. Shapiro, S. Yazdi, T. E. Mallouk, S. J. Osher, H. C. Kapteyn, V. H. Crespi, J. V. Badding, Y. Tserkovnyak, M. M. Murnane and J. Miao, “Three-dimensional topological magnetic monopoles and their interactions in a ferromagnetic meta-lattice”, Nature Nanotechnology, vol. 18, pp. 227–232, 2023. (Link to article)
L. Clark, G. T. Martinez, C. M. O'Leary, H. Yang, T. C. Petersen, S. D. Findlay and P. D. Nellist, “The effect of dynamical scattering on single-plane phase retrieval in electron ptychography”, Microscopy and Microanalysis, vol. 29, no. 1, pp. 384–394, 2023. (Link to article)
C. M. O’Leary*, B. Haas*, C. T. Koch, P. D. Nellist and L. Jones, “Increasing Spatial Fidelity and SNR of 4D-STEM using Multi-Frame Data Fusion”, Microscopy and Microanalysis, vol. 28, no. 4, pp. 1417–1427, 2022. (Link to article)
W. Song, M. A. Pérez-Osorio, J.-J. Marie, E. Liberti, X. Luo, C. M. O’Leary, R. A. House, P. G. Bruce and P. D. Nellist, “Direct imaging of oxygen shifts associated with the oxygen redox of Li-rich layered oxides”, Joule, vol. 6, no. 5, pp. 1049–1065, 2022. (Link to article)
C. M. O’Leary, G. T. Martinez, E. Liberti, M. J. Humphry, A. I. Kirkland and P. D. Nellist, “Contrast transfer and noise considerations in focused-probe electron ptychography”, Ultramicroscopy, vol. 221, p. 113189, 2021. (Link to article)
C. M. O’Leary, C. S. Allen, C. Huang, J. S. Kim, E. Liberti, P. D. Nellist and A. I. Kirkland, “Phase reconstruction using fast binary 4D STEM data”, Applied Physics Letters, vol. 116, no. 12, p. 124101, 2020. (Link to article)
M. U. Rothmann, J. S. Kim, J. Borchert, K. B. Lohmann, C. M. O’Leary, A. A. Sheader, L. Clark et al., “Atomic-scale microstructure of metal halide perovskite”, Science, vol. 370, no. 6516, p. eabb5940, 2020. (Link to article)
T. Chen, I. Ellis, T. J. N. Hooper, E. Liberti, L. Ye, B. T. W. Lo, C. O’Leary et al., “Interstitial Boron Atoms in the Palladium Lattice of an Industrial Type of Nanocatalyst: Properties and Structural Modifications”, Journal of the American Chemical Society, vol. 141, no. 50, pp. 19616–19624, 2019. (Link to article)
J. Fatermans, A. J. den Dekker, K. Müller-Caspary, I. Lobato, C. M. O’Leary, P. D. Nellist and S. Van Aert, “Single Atom Detection from Low Contrast-to-Noise Ratio Electron Microscopy Images”, Physical Review Letters, vol. 121, no. 5, p. 056101, 2018. (Link to article)

Conference proceedings

C. M O’Leary, H. Sha, G. Varnavides and P. Ercius, “Non-Iterative Electron Ptychography With Relaxed Real-Space Sampling”, Microscopy and Microanalysis, vol. 31, no. S1, p. ozaf048.055, 2025. (Link to abstract)
C. M O’Leary, D. J. Chang, P. Ercius, P. D. Nellist, A. I. Kirkland and J. Miao, “Confessions of a Ptychopath: Detection, Dimensions, Damage and Despair”, Microscopy and Microanalysis, vol. 29, no. S1, pp. 432-433, 2023. (Link to abstract)
M. Zachman, C. M. O’Leary, D. Y. Chung, H. Hafiz, E. F. Holby, V. Stamenkovic and D. Cullen, “Atomic-scale Imaging of PGM-free Catalyst Active Sites by 30 keV 4D-STEM”, Microscopy and Microanalysis, vol. 27, no. S1, pp. 2976-2977, 2021. (Link to abstract)
C. O'Leary, E. Liberti, G. Martinez, C. Allen, C. Huang, M. Rothmann, H. Luo, J. Kim, L. Herz, H. Assender and L. Jones, “Focused-probe STEM Ptychography: Developments and Opportunities”. Microscopy and Microanalysis, vol. 26, no. S2, pp. 470-471, 2020. (Link to abstract)
C. M. O'Leary, E. Liberti, S. M. Collins, D. N. Johnstone, M. Rothmann, J. Hou, C. S. Allen, J. S. Kim, T. D. Bennett, P. A. Midgley, A. I. Kirkland and P. D. Nellist, “Electron Ptychography Using Fast Binary 4D STEM Data”, Microscopy and Microanalysis, vol. 25, no. S2, pp. 1662-1663, 2019. (Link to abstract)
C. M. O'Leary, G. T. Martinez, E. Liberti, M. J. Humphry, A. I. Kirkland and P. D. Nellist, “Contrast Transfer and Noise Minimization in Electron Ptychography”, Microscopy and Microanalysis, vol. 25, no. S2, pp. 64-65, 2019. (Link to abstract)
M. Huth, R. Ritz, C. M. O'Leary, I. Griffiths, P. Nellist, and H. Soltau, “Ultrafast Ptychography with 7500 Frames per Second”, Microscopy and Microanalysis, vol. 25, no. S2, pp. 40-41, 2019. (Link to abstract)
E. Liberti, G. T. Martinez, C. M. O'Leary, P. D. Nellist, and A. I. Kirkland, “Three-dimensional Electron Ptychography of Catalyst Nanoparticles using Combined HAADF STEM and Atom Counting”, Microscopy and Microanalysis, vol. 25, no. S2, pp. 8-9, 2019. (Link to abstract)
T. J. Pennycook, G. T. Martinez, C. M. O'Leary, H. Yang, and P. D. Nellist, “Efficient Phase Contrast Imaging via Electron Ptychography, a Tutorial”, Microscopy and Microanalysis, vol. 25, no. S2, pp. 2684-2685, 2019. (Link to abstract)
P. D. Nellist, G. T. Martinez, C. O'Leary, and L. Jones, “Exploring the Limits of Focused-Probe STEM Ptychography”, Microscopy and Microanalysis, vol. 24, no. S1, pp. 190-191, 2018. (Link to abstract)

Thesis

C. O’Leary, The development and applications of STEM ptychography using direct electron detectors, University of Oxford, 2020. (Link to thesis)

Technical reports

C. O’Leary* et al., “Research Collaborations: A guide for early career researchers by early career researchers”, League of European Research Universities (LERU) Graduate Summer School, 2019. (Link to report)

Invited talks

A Comparative Analysis of Iterative and Non-Iterative Electron Ptychography
- Sep 2024: Frontiers of Electron Microscpy and Materials Science (FEMMS), Catania, Italy.

Confessions of a Ptychopath: Detectors, Dimensions, Damage and Despair
- Jul 2023: Microscopy and Microanalysis Conference, Minneapolis, Minnesota, USA.

Focused-Probe STEM Ptychography: Developments and Opportunities
- Aug 2020: Microscopy and Microanalysis (Virtual) Conference, USA. (Link to abstract)

Electron Ptychography: Maximizing Contrast While Minimizing Dose
- Sep 2019: Oak Ridge National Laboratory, Tennessee, USA.
- Sep 2019: Max Planck Institute for Solid State Research, Stuttgart, Germany.
- Aug 2019: Molecular Foundry, Lawrence Berkeley National Laboratory, California, USA.

Focused-Probe Electron Ptychography
- Nov 2018: School of Physics, Trinity College Dublin, Ireland.