SCIENCE CHINA Materials, Volume 63 , Issue 9 : 1788-1796(2020) https://doi.org/10.1007/s40843-020-1320-1

X-ray imaging of atomic nuclei

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  • ReceivedFeb 7, 2020
  • AcceptedMar 30, 2020
  • PublishedApr 30, 2020



the National Key R&D Program of China(2017YFA0700104)

the National Science Fund for Distinguished Young Scholars(51825102)

the National Natural Science Foundation of China(51971157,51671145,51761165012)

and Tianjin Science Fund for Distinguished Young Scholars(19JCJQJC61800)


We thank Prof. Peng Gao from Peking University for providing the SrTiO3 sample, Ketao Zang and Kai Wang from Tianjin University of Technology for assistance in experiments, and Dr. Qiang Xu from Delft University of Technology, Dr. Shu Miao from JEOL, Dr. Guang Yang from FEI and Prof. Li-Min Liu from Beihang University for helpful discussion. The authors also acknowledge the National Supercomputing Center in Shenzhen for providing the computational resources and materials studio (version 7.0, DMol3). This work was financially supported by the National Key R&D Program of China (2017YFA0700104), the National Science Fund for Distinguished Young Scholars (51825102), the National Natural Science Foundation of China (51971157, 51671145 and 51761165012), and Tianjin Science Fund for Distinguished Young Scholars (19JCJQJC61800).

Interest statement

The authors declare no conflict of interest.

Contributions statement

Luo J proposed and designed ANXRI and its schemes of experiments and calculations, and he also supervised the project. Luo J and Xu J co-performed the main experiments and co-analyzed all experimental results, to which Ding Y contributed. He J performed the DFT calculations and analyzed the results, to which Luo J, Ding Y and Xu J contributed.

Author information

Jie Xu received his BSc degree from the School of Materials Science and Engineering at Tianjin University of Technology, China, in 2016. His current interests include low-dimensional materials and their electron microscopy and optical imaging.

Jun Luo received his BSc (2001) and PhD (2006) degrees from Tsinghua University, China. Then, he worked as a postdoc at Warwick University and a research fellow at Oxford University, UK. In 2011, he joined Tsinghua University as an associate professor. In 2015, he moved to Tianjin University of Technology and is a full professor in the Center for Electron Microscopy. His research interests focus on low-dimensional materials and their electron microscopy and optical imaging.

Supplementary data

Supplementary information

Detailed analyses and supporting data are available in the online version of the paper.


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  • Figure 1

    Working mechanisms of AFM and ANXRI. (a, b) Schematic images for the mechanism of AFM when the tip of its cantilever scans a valley and a peak, respectively, on the surface of a sample. During the scanning, the tip is displaced, and its displacements are recorded with the laser beam, giving the topographic curves in the boxes. (c, d) Schematic images for the proposed mechanism of ANXRI when two incident electrons of its electron beam pass by two positions close to and closer to, respectively, the center of an atomic nucleus. The circles represent the Coulombic-field energy distribution of the nucleus. Due to the Coulombic field, the two incident electrons are decelerated, producing bremsstrahlung and thus emitting X-ray photons [13].

  • Figure 2

    Characterization and ANXRI results of NPG–Pd–Pt, which is a real-world catalyst [9], by JEOL JEM-ARM 300F. (a) Atomically resolved elemental mapping image of the sample using the characteristic EDS peak counts of Au (green), Pd (red) and Pt (blue). Reproduced with permission from Ref. [9]. Copyright 2017, Springer Nature. (b) EDS spectrum from the region in (a). The green-colored energy ranges denoted by E1 and E2 in the background are from 3.53 to 4.29 keV and from 5.24 to 6 keV, respectively, and they have the same width of 0.76 keV (see the Experimental Section and the caption of Fig. S1 for the origins of the characteristic EDS peaks of Ti and Fe and the criteria to choose the energy windows). (c, d) ANXRI images of atomic nuclei obtained by using the counts in the E1 and E2 ranges in (b) for mapping. The images have the same scale bars as that in (a).(e, f) FFT patterns of (c) and (d), in each of which six diffraction spots exist and two of them are indicated by arrows as examples.

  • Figure 3

    Adjustment of the individual imaged sizes of the atomic nuclei of NPG–Pd–Pt. (a, b) Images of the atomic nuclei, which are identical to Fig. 2c, d, respectively. In the images, 20 dots are randomly selected and then numbered. (c, d) FWHM values of the 20 dots. The black and the red values were measured in (a) and (b), respectively. It should be noted that all the results in Figs 2 and 3 were achieved using JEOL JEM-ARM 300F on NPG–Pd–Pt, which is a real-world catalyst with nonuniform thickness [9]. We re-performed the experiments with FEI Titan Cubed Themis G2 300 on the well-defined sample of SrTiO3 with uniform thickness and another type of real-world catalyst (NPG without Pd or Pt [9,29]). Their results also give the images of atomic nuclei and are also consistent with the ANXRI prediction (Figs S4–S8 and Tables S4, S5).

  • Figure 4

    Characterization and ANXRI analysis of the SrTiO3 sample by FEI Titan Cubed Themis G2 300. (a) Atomically resolved elemental mapping image of the sample using the characteristic EDS peak counts of Sr (red), Ti (green) and O (blue). Each Ti atom column contains O atoms with the Ti/O ratio of 1:1, and thus it is denoted as Ti/O, for which the overlay of green and blue gives cyan. (b) ANXRI image of atomic nuclei obtained by using the counts in the E1 range in (c) for mapping, which has the same scale bar as (a). The dots labeled by the red and the blue numbers are located at the positions of Sr and Ti/O columns, respectively, and the numbers of only four dots are drawn here for clear visualization (128 dots are numbered; please see all 128 numbers in Figs S8 and S10a). (c) EDS spectrum from the region in (a). The E1 and E2 ranges have the same width of 0.9 eV (see the Experimental Section for the origins of the characteristic EDS peaks of Fe, Co and Cu). (d) FWHM values of the labeled 128 dots, which all correspond to E1. The dashed lines indicate the positions of the maxima and the minima.


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