films with high room-temperature electron mobility*

Bulk SrSnO₃ (SSO) exhibits four crystalline polymorphs as a function of temperature. Through comprehensive thin film growth using novel radical-based MBE approach, synchrotron x-ray scattering, electronic transport, and first-principles calculations, we report on the stabilization of different polymorphs of SSO at room temperature (RT), in thin film form. Compressive strain stabilized the high-symmetry tetragonal phase of SSO at RT, which, in bulk, exists only at temperatures between 1062 K and 1295 K. A mobility enhancement of over 300% in the doped tetragonal phase of SSO films compared with the low-temperature orthorhombic polymorph was achieved. We will discuss these results in the context of the role of strain, doping, and disorder on structure and electronic transport of doped SSO films.