2016 - present: Assistant Physicist: X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, USA

2014 - 2016: Postdoctoal Appointee, Materials Science Division, Argonne National Laboratory, USA

Wonsuk Cha, Yihua Liu, Hoydoo You, Gregory Brian Stephenson, and Andrew Ulvestad, Dealloying in Individual Nanoparticles and Thin Film Grains: A Bragg Coherent Diffractive Imaging Study, Accepted by Advanced Functional Materials.

Allison Yau, Wonsuk Cha, Matthew W. Kanan, G. Brian Stephenson, Andrew Ulvestad, Bragg coherent diffractive imaging of single-grain defect dynamics in polycrystalline films, Science 358, 739-742 (2017).

Y. Liu, P. P. Lopes, W. Cha, R. Harder, J. Maser, E. Maxey, M. J. Highland, N. M. Markovic, S. O. Hruszkewycz, G. B. Stephenson, H. You, and A. Ulvestad, Stability Limits and Defect Dynamics in Ag Nanoparticles Probed by Bragg Coherent Diffractive Imaging, Nano Letters 17, 1595-1601 (2017).

S. O. Hruszkewycz, W. Cha, P. Andrich, C. P. Anderson, A. Ulvestad, R. Harder, P. H. Fuoss, D. D. Awschalom, and F. J. Heremans, In situ study of annealing-induced strain relaxation in diamond nanoparticles using Bragg coherent diffraction imaging, APL Materials 5, 026105 (2017).

A. Ulvestad, M. J. Welland, W. Cha, Y. Liu, J. W. Kim, R. Harder, E. Maxey, J. N. Clark, M. J. Highland, H. You, P. Zapol, S. O. Hruszkewycz and G. B. Stephenson, Three-dimensional imaging of dislocation dynamics during the hydriding phase transformation, Nature Materials 16, 565-571 (2017).

Mathew J. Cherukara, Kiran Sasikumar, Wonsuk Cha, Badri Narayanan, Steven J. Leake, Eric M. Dufresne, Tom Peterka, Ian McNulty, Haidan Wen, Subramanian K. R. S. Sankaranarayanan, and Ross J. Harder, Ultrafast Three-Dimensional X‑ray Imaging of Deformation Modes in ZnO Nanocrystals, Nano Letters 17, 1102-1108 (2017).

W. Cha, A. Ulvestad, M. Allain, V. Chamard, R. Harder, S. J. Leake, J. Maser, P. H. Fuoss, and S. O. Hruszkewycz, Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging, Physical Review Letters 117, 225501 (2016).

Wonsuk Cha, Wenjun Liu, Ross Harder, Ruqing Xu, Paul H. Fuoss, Stephan O. Hruszkewycz, Utilizing broadband x-rays in a Bragg coherent x-ray diffraction imaging experiment, Journal of Synchrotron Radiation 23, 1241-1244 (2016).

Jerome Carnis, Wonsuk Cha, James Wingert, Jinback Kang, Zhang Jiang, Sanghoon Song, Marcin Sikorski, Aymeric Robert, Christian Gutt, San-Wen Chen, Yeling Dai, Yicong Ma, Hongyu Guo, Laurence B. Lurio, Oleg Shpyrko, Suresh Narayanan, Mengmeng Cui, Irem Kosif, Todd Emrick, Thomas P. Russell, Hae Cheol Lee, Chung-Jong Yu, Gerhard Grübel, Sunil K. Sinha and Hyunjung Kim, Demonstration of Feasibility of X-Ray Free Electron Laser Studies of Dynamics of Nanoparticles in Entangled Polymer Melts, Scientific Reports 4, 6017 (2014).

Chung-Jong Yu, Hae Cheol Lee, Chan Kim, Wonsuk Cha, Jerome Carnis, Yoonhee Kim, Do Young Noh, Hyunjung Kim, Coherent X-ray Scattering Beamline at the Port 9C of the Pohang Light Source II, Journal of Synchrotron Radiation 21, 264-267 (2014).

Wonsuk Cha, Nak Cheon Jeong, Sanghoon Song, Hyun-jun Park, Tung Cao Thanh Pham, Ross Harder, Bobae Lim, Gang Xiong, Docheon Ahn, Ian Mcnulty, Jungho Kim, Kyung Byung Yoon, Ian K Robinson, and Hyunjung Kim, Core-Shell Strain Structure of Zeolite Microcrystals, Nature Materials 12, 729-734 (2013).

Wonsuk Cha, Sanghoon Song, Nak Cheon Jeong, Ross Harder, Kyung Byung Yoon, Ian K Robinson, and Hyunjung Kim, Exploration of crystal strains using coherent x-ray diffraction, New Journal of Physics 12, 035022 (2010).

My research focuses on discovering the relationship between structure and property using and developing new coherent x-ray diffraction techniques.

• Revealing structure/property relationships in nanomaterials with in-situ coherent x-ray diffraction imaging by examining deformation field distributions
• Utilizing broadband coherent x-rays for fast measurements for coherent x-ray diffraction imaging in Bragg geometry
• Investigating atomic structure of thin films with x-ray scattering techniques, such as grazing incidence small angle scattering and x-ray reflectivity
• Developing new instruments for in-situ catalysis or phase transition experiments

2014: Ph. D, Physics, Sogang University, Seoul, Korea

2009: M. S., Engineering (Interdisciplinary Program of Integrated Biotechnology), Sogang University, Seoul, Korea

2007: B. S., Physics and Mathematics, Sogang University, Seoul, Korea

Scientist of Beamline 34-ID-C of the Advanced Photon Source for scientific program, operation, and user support

Chair of Gordon Research Seminar in X-ray Science (2017)