摘要:SummaryNanotwin structures in materials engender fascinating exotic properties. However, twinning usually alter the crystal orientation, resulting in random orientation and limited performances. Here, we report a well-aligned rutile TiO2nanotwin film with superior preferential orientation than its isostructural substrate. By means of the synchrotron X-ray Laue nanodiffraction technique, the crystal orientation, twin boundaries, and deviatoric stresses of the film were quantitatively imaged at unprecedented spatial resolution to unravel the underlying mechanism of this anomalous alignment. Massive {101}-type rutile nanotwins were observed, and a crystallographic relationship of the heteroepitaxy was proposed. The rapid twinning and twin-controlled heteroepitaxy are responsible for the texture improvement. This work would open up opportunities for rational design of better twin-based functional materials, and implies the powerful capabilities of X-ray nanodiffraction technique for multidisciplinary applications.Graphical abstractDisplay OmittedHighlights•Nanotwinned TiO2film possesses stronger preferred orientation than its FTO substrate•State-of-the-art nanoscanned X-ray Laue diffraction is used to unveil the mechanism•Twinning-mediated heteroepitaxy mainly leads to the texture improvement•This work helps to stimulate the rational design and synthesis of nanotwin materialsMaterials Science; Materials Characterization Techniques; Crystallography