Application and development of three-dimensional differential pair distribution function method in Shanghai Synchrotron Radiation Facility

<bold>Background</bold>In recent years, the three-dimensional differential atomic pair distribution function (3D-ΔPDF) method has gained extensive attention from researchers in synthetic chemistry, condensed matter physics, and materials science due to its unique advantages in probing local material structures. The high brightness and intensity of next-generation synchrotron radiation sources enable 3D-ΔPDF to provide unprecedented atomic-level precision in characterizing local material structures.<bold>Purpose</bold>This study aims to implement the 3D-ΔPDF method at different energy beamlines of Shanghai Synchrotron Radiation Facility (SSRF) and validate its effectiveness and reproducibility for analyzing local structures in single-crystal materials.<bold>Methods</bold>Firstly, single crystal X-ray diffraction experiments were conducted on PbTe and Zr_0.91Y_0.09O₂ (YSZ) samples at the BL12SW beamline of SSRF using energies of 101.2 keV (<italic>λ</italic>=0.122 5 Å) and 98.5keV (<italic>λ</italic>=0.125 8 Å), respectively. Then, three-dimensional total scattering datasets were collected by rotating the samples continuously through more than 180° around the phi axis, with diffraction images captured at 1° intervals. Finally, the 3D-ΔPDF method was applied to remove Bragg diffraction signals, allowing direct analysis of correlation functions in three-dimensional space.<bold>Results</bold>The experimental results show that under low-temperature conditions (150 K), thermal vibration-induced diffuse scattering is significantly reduced, enhancing the resolution of 3D-ΔPDF experiments by approximately 18% compared to room temperature measurements. Local symmetry breaking in the PbTe system and strong correlations along the &lt;100&gt; direction are revealed by 3D-ΔPDF analysis, providing structural insights into its exceptional thermoelectric properties. Additionally, comparative results show that the 5858E detector exhibits 22.5% higher signal detection efficiency (<italic>Q</italic>_max of 383.1 nm^-1<italic>vs</italic>. 312.8 nm^-1 for PILATUS 2M) under identical beam conditions, significantly improving real-space resolution and capturing finer 3D-ΔPDF details.<bold>Conclusions</bold>The successful implementation of the 3D-ΔPDF method at SSRF, proposed in this study, validate its accuracy and reproducibility for precisely identifying and analyzing local structural changes in materials, making it as an essential characterization method for advancing materials science research in SSRF with implications for energy, environmental, and high-technology applications. The improved experimental setup, including low-temperature capabilities down to 28 K and advanced detectors, establishes a robust platform in SSRF for investigating structure-property relationships in functional materials.