Jianwei (John) Miao is a Professor in the Department of Physics and Astronomy and the California NanoSystems Institute at the University of California, Los Angeles. He performed the first experiment on extending crystallography to allow structural determination of non-crystalline specimens in 1999,[1] which has been known as coherent diffractive imaging (CDI), lensless imaging, or computational microscopy.[2] In 2012, Miao applied the CDI method to pioneer atomic electron tomography (AET), enabling the first determination of 3D atomic structures without assuming crystallinity or averaging.[3][4]
Miao pioneered the development of novel imaging methods using x-rays and electrons, and contributed to theory, computation, and experiment. He proposed the oversampling ratio concept in 1998, which explains under what conditions the phase problem of non-crystalline specimens can be solved.[7] In 1999, he conducted the first CDI experiment[1] at the National Synchrotron Light Source, Brookhaven National Laboratory. CDI methods, such as plane-wave CDI, ptychography[8] (i.e., scanning CDI[9]) and Bragg CDI, have been broadly implemented using synchrotron radiation, x-ray free electron lasers, high harmonic generation, electron and optical microscopy.[2] It has also become one of the justifications for the construction of x-ray free electron lasers worldwide.[2]
In 2012, Miao applied CDI phase retrieval algorithms to tomography and demonstrated AET at 2.4 Å resolution without assuming crystallinity.[3] He then applied AET to observe nearly all the atoms in a Pt nanoparticle,[10] and imaged the 3D core structure of edge and screw dislocations at atomic resolution.[11] In 2015, he determined the 3D coordinates of thousands of individual atoms in a material with a 3D precision of 19 pm and addressed Richard Feynman’s 1959 challenge.[12] Later, Miao measured the 3D coordinates of more than 23,000 atoms in an FePt nanoparticle, and correlated chemical order/disorder and crystal defects with material properties at the single-atom level.[13] In 2019, he developed 4D AET to observe crystal nucleation at atomic resolution, showing early stage nucleation results contradict classical nucleation theory.[14] Miao also demonstrated scanning AET (sAET) to correlate the 3D atomic defects and electronic properties of 2D materials.[15] In 2021, he determined for the first time the 3D atomic structure of amorphous solids and observed the medium-range order in amorphous materials.[16][17][18]
^Miao, J.; Sayre, D.; Chapman, H. N. (1998). "Phase Retrieval from the Magnitude of the Fourier transform of Non-periodic Objects". J. Opt. Soc. Am. A. 15 (6): 1662–1669. Bibcode:1998JOSAA..15.1662M. doi:10.1364/JOSAA.15.001662.
^Chen, C. C.; Zhu, C.; White, E. R.; Chiu, C.-Y.; Scott, M. C.; Regan, B. C.; Marks, L. D.; Huang, Y.; Miao, J. (2013). "Three-dimensional imaging of dislocations in a nanoparticle at atomic resolution". Nature. 496 (7443): 74–77. Bibcode:2013Natur.496...74C. doi:10.1038/nature12009. PMID23535594. S2CID4410909.
^Xu, R.; Chen, C.-C.; Wu, L.; Scott, M. C.; Theis, W.; Ophus, C.; Bartels, M.; Yang, Y.; Ramezani-Dakhel, H.; Sawaya, M. R.; Heinz, H.; Marks, L. D.; Ercius, P.; Miao, J. (2015). "Three-Dimensional Coordinates of Individual Atoms in Materials Revealed by Electron Tomography". Nat. Mater. 14 (11): 1099–1103. arXiv:1505.05938. Bibcode:2015NatMa..14.1099X. doi:10.1038/nmat4426. PMID26390325. S2CID5455024.
^Yang, Y.; Chen, C.-C.; Scott, M. C.; Ophus, C.; Xu, R.; Pryor Jr, A.; Wu, L.; Sun, F.; Theis, W.; Zhou, J.; Eisenbach, M.; Kent, P. R. C.; Sabirianov, R. F.; Zeng, H.; Ercius, P.; Miao, J. (2017). "Deciphering chemical order/disorder and material properties at the single-atom level". Nature. 542 (7639): 75–79. arXiv:1607.02051. Bibcode:2017Natur.542...75Y. doi:10.1038/nature21042. PMID28150758. S2CID4464276.
