Uncovering the interfacial structures at the atomic scale is crucial for understanding and tailoring the emergent phenomena at the interfaces between nitrides and oxides. However, synthesizing high-quality interfaces with extremely large lattice mismatch and varied crystal symmetries remains a challenge. In this study, we reveal a rare interfacial coincidence structure with periodic misfit dislocations between the rocksalt nitride TiN and the perovskite oxide ${\mathrm{YAlO}}_3$, utilizing a combination of high-resolution x-ray diffraction and atomic resolution scanning transmission electron microscopy. The coincidence structure, with 3.5 units of TiN matching 4 units of ${\mathrm{YAlO}}_3$, facilitates the formation of high-quality interfaces, despite a lattice mismatch as large as $-15.4\%$ between TiN and ${\mathrm{YAlO}}_3$. Furthermore, compared the TiN films coherently grown on MgO substrates, electrical transport measurements uncover that the coincidence interface between TiN and ${\mathrm{YAlO}}_3$ with strain relaxation can lead to a higher superconducting transition temperature of 5.33 K compared to 5.02 K. Our work reveals an unconventional interfacial mechanism for forming high-quality heterostructures composed of materials with extremely large lattice mismatch. Moreover, it paves a way to tailor the electronic properties of functional layers by controlling the interfacial structures.

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• Crystal structure
• Growth
• Surface & interfacial phenomena
• Interfaces
• Thin films
• Epitaxy
• Scanning transmission electron microscopy