Twin-Domain Formation in Epitaxial Triangular Lattice Delafossites

Twin domains are often found as structural defects in symmetry mismatched epitaxial thin films. The delafossite ABO2, which has a rhombohedral structure, is good example that forms twin domains. Although bulk metallic delafossites known to be the most conducting oxides, high conductivity yet realized film forms. Suppressed films mainly caused by formation of domains, and their boundaries can source scattering centers for charge carriers. To overcome this challenge, underlying mechanism must understood so such controlled eliminated. Here, we report origin twins formed CuCrO2 on substrate with hexagonal or triangular symmetries. A robust heteroepitaxial relationship substrate, surface termination turns out critical determine control domain structure delafossites. Based discoveries, also demonstrate twin-free grown high-miscut substrates. This finding provides an important synthesis strategy growing single-domain applied other high-quality