Strain Programming of Oxygen Octahedral Symmetry for Correlated Topological Oxides

Quantum materials (QMs) with strong correlation and nontrivial topology are indispensable to next-generation information and computing technologies. The exploitation of topological band structure is an ideal starting point to realize correlated topological QMs. Among many classes of QMs, complex oxides offer a huge opportunity to exploit both correlations of Coulombic interactions between electrons and spin-orbit coupling, leading to many intriguing physical properties. Despite the huge potential, however, there are limited discoveries on oxide-based topological QMs. Here, we report a new strategy to develop oxide-based correlated topological QMs by strain and nonsymmorphic symmetry engineering that yielded oxide Dirac semimetals with extreme high mobility and magnetoresistance. The physical properties are among the best from complex oxides. Epitaxial synthesis of high-quality 4d TMOs thin films, including SrNbO₃ and CaNbO₃, with precisely tunned octahedral symmetry by strain and their structural and physical properties will be presented.