Twinning-mediated anomalous alignment of rutile films revealed by synchrotron X-ray nanodiffraction

Nanotwin 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 TiO2 nanotwin 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.

Automated summary

The study reported a well-aligned rutile TiO2 nanotwin film with superior preferential orientation compared to its isostructural substrate. Through synchrotron X-ray Laue nanodiffraction technique, the crystal orientation, twin boundaries, and deviatoric stresses were quantitatively imaged to unravel the underlying mechanism of this anomalous alignment. Massive {101}-type rutile nanotwins were observed, with a proposed crystallographic relationship of the heteroepitaxy. The rapid twinning and twin-controlled heteroepitaxy were found to be responsible for the texture improvement, emphasizing the potential of X-ray nanodiffraction technique for multidisciplinary applications.