Fig. 5. Twinning nucleation assisted by the strain field of a matrix dislocation.

a–d Sequential HRTEM images showing the nucleation of a twin embryo near the dislocation core (indicated by the “├” symbol). The crystal was under <1 −1 0 0 > -oriented compression and viewed along the <1 1 −2 0> direction. White dashed line in a is the Burgers circuit which indicates an <a > component in the Burgers vector (indicated by the yellow arrow) of the dislocation. Detailed analysis of the Burgers vector is shown in Supplementary Fig. 5. e Mapping of the strain normal to the parent prismatic plane (ε_yy) generated by the dislocation core, by geometrical phase analysis. Boxed region is the reference region for the geometrical phase analysis (see ref. ⁵⁶ for more details). f–g Inverse fast Fourier transformations of the TEM snapshots in b, c, respectively, using the (0 0 0 1) reflections of the twin (indicated by turquoise-circles in h). Turquoise dotted circles in b, c, f, g mark the twin embryo. White circles and lines in h indicate the reciprocal lattice of the matrix. Scale bars in a–d, 2 nm.