fig2

Figure 2. Structural characterizations of the 5 GPa sample using transmission electron microscopy (TEM); (A) Low-resolution TEM image showing the clear grain boundaries; (B) High-resolution TEM (HRTEM) image and fast Fourier transformation (FFT) analysis (inset) indicating a cubic phase view along the [001] direction; (C) A close-up view of atomic arrangement with corresponding atomic model of cubic SrTiO₃; (D) TEM image and energy dispersive spectrum (EDS) mapping of the elements Sr, La, Eu, Sm, Nd, revealing the dopants are concentrated at the grain boundary; (E and F) High-magnification images of the grain boundary, with brightness variations indicating elemental enrichment; (G) HRTEM image and (H) inverse fast Fourier transformation (IFFT) analysis illustrating lattice distortions and edge dislocations; (I-L) Corresponding strain maps of Figure 2(C) analyzed by geometric phase analysis (GPA) method.