Crystal phase control in an YBiO₃ thin film by using a BaBiO₃ buffer layer

Topological insulating materials are very promising for applications in spintronics and quantum computing. The presently confirmed topological insulators are not suitable for room temperature applications. Perovskite oxides are interesting in this respect, since topological insulating phases have theoretically been predicted with large band gaps. YBiO₃ has been predicted to be a topological insulator for the perovskite phase with yttrium and bismuth located at the A-site and B-site, respectively. However, the fluorite phase turns out to be thermodynamically more stable than the perovskite phase. In this work we show that we were able to engineer the perovskite crystal phase of thin film YBiO₃ by using a BaBiO₃ buffer layer and interval deposition. When the YBiO₃ is deposited on top of the BaBiO₃, a single oriented perovskite phase is observed with the expected lattice constants. These findings pave a way towards the fabrication of quantum devices for testing the hypothesized topological insulating phase in YBiO₃.