People

Colin Ophus(he/him)

Group Leader

Colin received his BSc in Engineering Physics, and his PhD in Materials Engineering in David Mitlin’s group at the University of Alberta in Edmonton, Canada. He received an NSERC scholarship to pursue postdoctoral research working for Velimir “Mimo” Radmilovic at Berkeley Lab and Mark Asta at UC Berkeley. He then worked as a Project Scientist, Research Scientist, and Staff Scientist at the National Center for Electron Microscopy (NCEM), part of the Molecular Foundry user facility at Lawrence Berkeley Lab.

Colin Ophus lab’s research focuses on experimental methods, reconstruction algorithms, and software codes for simulation, analysis, and instrument design of TEM, STEM and 4DSTEM. He was awarded a US Department of Energy (DOE) Early Career award in 2018, and the Burton Medal from the MSA in 2022. He has published over 200 peer-reviewed publications, and given over 100 invited talks and workshops around the world. Colin advocates for open science and his group develops open-source scientific software such as the py4DSTEM analysis and Prismatic STEM simulation. He is also the editor-in-chief for the interactive web-based scientific journal Elemental Microscopy.

Postdoctoral Researchers

Stephanie Ribet(she/her)

Postdoctoral Researcher

Steph received her PhD at Northwestern University in the Dravid Group. During her PhD, she was award an SCGSR from the US Department of Energy for a research internship at Berkeley Lab. She is currently a postdoc working in Colin’s group at Stanford and in Karen Bustillo’s group at Berkeley Lab.

Uncovering the 3D structure of upconverting core–shell nanoparticles with multislice electron ptychography

Arthur McCray(he/him)

Postdoctoral Researcher

Arthur McCray received his PhD in Applied Physics at Northwestern University, supervised by Amanda Petford-Long. He has experience in Lorentz TEM, magnetic materials, and is currently developing machine learning methods for solving inverse problems in (S)TEM. Arthur is also the lead developer of the pyLorentz software package.

AI-enabled Lorentz microscopy for quantitative imaging of nanoscale magnetic spin textures

Georgios Varnavides(he/him)

Postdoctoral Researcher

Georgios Varnavides is a postdoctoral Miller research fellow at the University of California, Berkeley, where he is developing new computational imaging modalities to observe structure and function in materials with high spatial resolution.

Iterative phase retrieval algorithms for STEM

Serin Lee(she/her)

Postdoctoral Researcher

Serin earned her PhD in Materials Science and Engineering at MIT, advised by Professor Frances Ross, as an MIT Energy Initiative and MathWorks Fellow. She is one of Northwestern’s 10 Future Leaders in Materials Science. Her research uses in situ electron microscopy to study nanomaterials for sustainability, while her postdoc focuses on enhancing photocatalytic materials’ performance and lifetime with advanced techniques like 4DSTEM. Serin is also active in community building and mentorship, serving on the Early Career Committee of the MSA and mentoring through Stanford’s Science Small Group program.

Temperature dependent nanochemistry and growth kinetics using liquid cell TEM

PhD Students

Andrew Ducharme(he/him)

PhD Student

Andrew is a PhD candidate in the Department of Physics at the University of Oregon, supervised by Ben McMorran. He was awarded an SCGSR fellowship from the US Department of Energy to work on STEM holography-pytchography in Colin’s group at Berkeley Lab and Stanford.

Samuel Gleason(he/him)

PhD Student

Sam is a Physical Chemistry PhD candidate at the University of California, Berkeley. He is a member of the research group of Paul Alivisatos and is completing his doctoral research at the National Center For Electron Microscopy, co-supervised by Colin and Dr Jim Ciston.

Random forest prediction of crystal structure from electron diffraction patterns incorporating multiple scattering

Student Rotations

Antony Georgiadis(he/him)

PhD Student

Antony is a PhD candidate in Materials Science and Engineering at Stanford University coming from the University of Rochester where he earned a BS and MS in Optics. He is interested in computational imaging applied to materials science, scientific communication, and creating novel devices for environmental sensing.

Cedric Lim(he/him)

Masters Student

Cedric earned his B.A in Physics at the University of California, Berkeley. He worked with Professor Anatoli Polkovnikov at Boston University proposing a new definition of chaos in both classical and quantum systems. He is currently interested in machine learning and experimental techniques used in 4DSTEM.

Defining classical and quantum chaos through adiabatic transformations

Administrators

Chris Hall(he/him)

Administrator

Chris has worked in MSE Administration for a little over a year, after previous administrative positions at Stanford. Please let him know if he can help with anything.

Former Members

Benjamin Savitzky

Former Member

Formerly a PhD student in Lena Kourkoutis’ group at Cornell and a postdoc in Colin Ophus’ group at Berkeley Lab. Now working as a Principle Research Scientist at hBar Instruments.

py4DSTEM: A Software Package for Four-Dimensional Scanning Transmission Electron Microscopy Data Analysis

Alexander Rakowski

Former Member

Received his PhD in Sarah Haigh’s group at Manchester, and worked a postdoc in Joe Patterson and Colin Ophus’ group. Now returned to silicon valley.

Disentangling multiple scattering with deep learning: application to strain mapping from electron diffraction patterns

Philipp Pelz

Former Member

Philipp Pelz received Bachelor degrees in Physics (2011) and Informatics (2012), and Master degrees in Applied & Engineering Physics, Materials Science & Chemistry (2013). In 2018 he obtained his Ph.D. in Physics from the University of Hamburg & The Max Planck Institute for the Structure and Dynamics of Matter, Germany. Subsequently, he spent three years as a postdoctoral researcher at the University of California, Berkeley and the National Center for Electron Microscopy. Since August 2022 he is Tenure-Track Professor for Computational Materials Microscopy at FAU Erlangen-Nürnberg.

Solving complex nanostructures with ptychographic atomic electron tomography

Ellis Kennedy

Former Member

Received her PhD in Mary Scott’s group at UC Berkeley after interning in Colin’s group and Mary’s group. Formerly a postdoc in Kwabena Bediako’s group at UC Berkeley, and now working as a postdoc at Los Alamos National Lab.

Tilted fluctuation electron microscopy

Steven Zeltmann

Former Member

Received his PhD in Andy Minor’s group at UC Berkeley. Now working as a Staff Scientist in PARADIM at Cornell University.

Alexandra Bruefach

Former Member

Received PhD in Mary Scott’s group at UC Berkeley. Now working as a Research Scientist at Meta.

Automated crystal orientation mapping in py4DSTEM using sparse correlation matching

Blanka Janicek

Former Member

Received her PhD in Pinshane Huang’s group at UIUC. Worked as postdoc in Xi Jiang’s group and Colin Ophus’ group at Berkeley Lab. Currently a Scientist working at Exponent.

Structural complexities in sodium ion conductive antiperovskite revealed by cryo-TEM

Hannah Devyldere

Former Member

Former intern in Colin Ophus’ group. Currently pursuing a PhD in Mary Scott’s group at UC Berkeley.

Luis Rangel DaCosta

Former Member

Former intern in Colin Ophus’ group. Currently pursuing a PhD in Mary Scott’s group at UC Berkeley.

Prismatic 2.0 – Simulation software for STEM and HRTEM

Thomas Pekin

Former Member

Graduated PhD program in Andrew Minor’s group at UC Berkeley. Postdoc in Christoph Koch’s group at Humboldt Universität zu Berlin. Now a Team Product Owner at Carl Zeiss SMS.

Optimizing disk registration algorithms for nanobeam electron diffraction strain mapping

Rohini Sankaran

Former Member

Received her PhD from Andy Minor’s group and Daryl Chrzan’s group at UC Berkeley. Worked as a Sr. Failure Analysis R&D Engineer at Intel. Currently a Staff Scientist at Lawrence Livermore National Lab.

HAADF imaging of the omega (ω) phase in a gum metal-related alloy

Hao Yang

Former Member

Received his PhD from Pete Nellist’s group at Oxford. Formerly a postdoc in Colin Ophus’ group. Currently working in industry.

Milena Loper

Former Member

Former intern in Colin Ophus’ group.

Iris You

Former Member

Former intern in Colin Ophus’ group.

Levi Brown

Former Member

Former intern in Colin Ophus’ group.

References
  1. Ribet, S. M., Varnavides, G., Pedroso, C. C. S., Cohen, B. E., Ercius, P., Scott, M. C., & Ophus, C. (2024). Uncovering the three-dimensional structure of upconverting core–shell nanoparticles with multislice electron ptychography. Applied Physics Letters, 124(24). 10.1063/5.0206814
  2. McCray, A. R. C., Zhou, T., Kandel, S., Petford-Long, A., Cherukara, M. J., & Phatak, C. (2024). AI-enabled Lorentz microscopy for quantitative imaging of nanoscale magnetic spin textures. Npj Computational Materials, 10(1). 10.1038/s41524-024-01285-8
  3. Varnavides, G., Ribet, S. M., Zeltmann, S. E., Yu, Y., Savitzky, B. H., Byrne, D. O., Allen, F. I., Dravid, V. P., Scott, M. C., & Ophus, C. (2023). Iterative Phase Retrieval Algorithms for Scanning Transmission Electron Microscopy. arXiv. 10.48550/ARXIV.2309.05250
  4. Lee, S., Schneider, N. M., Tan, S. F., & Ross, F. M. (2023). Temperature Dependent Nanochemistry and Growth Kinetics Using Liquid Cell Transmission Electron Microscopy. ACS Nano, 17(6), 5609–5619. 10.1021/acsnano.2c11477
  5. Savitzky, B. H., Zeltmann, S. E., Hughes, L. A., Brown, H. G., Zhao, S., Pelz, P. M., Pekin, T. C., Barnard, E. S., Donohue, J., Rangel DaCosta, L., Kennedy, E., Xie, Y., Janish, M. T., Schneider, M. M., Herring, P., Gopal, C., Anapolsky, A., Dhall, R., Bustillo, K. C., … Ophus, C. (2021). py4DSTEM: A Software Package for Four-Dimensional Scanning Transmission Electron Microscopy Data Analysis. Microscopy and Microanalysis, 27(4), 712–743. 10.1017/s1431927621000477
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