Electron irradiation induced rock salt type structure from ZnO/Zn intergrowth

摘要

Electron irradiation of nano-size wurtzite (W)-type ZnO condensates with intimate mixture of parallel epitaxial Zn caused {1 0 1-bar 1 }_w slip to form a single domain of rock salt (R)-type core and W-type shell. The two polymorphs follow (1 1-bar l)_R//(0 1-bar 1 l)_w; [0 1 1]_R//[ 1-bar 2 1-bar 3]_w, i.e. chair type Peierls distortion with additional 38 deg tilting (0 0 1)_R along the (1-bar 2 1-bar 0)_w plane for a fair match of (1 0 1-bar 1)_w/(1 1-bar 1)_R, the same as one of the two paths for the back-transformation of R-ZnO into a lower crystal symmetry. The martensitic nucleation of R-type ZnO can be attributed to dynamic migration of interstitials/vacancies, lattice mismatch stress, and capillarity effect.