Selective growth of Ruddlesden-Popper strontium iridate epitaxial films by controlling oxygen partial pressure in pulsed laser deposition

The Ruddlesden-Popper (RP)-type strontium iridate (SrIrO₃ and Sr₂IrO₄) epitaxial thin films are selectively grown from a single Sr₂IrO₄ target using pulsed laser deposition. The stabilization of the SrIrO₃ and Sr₂IrO₄ phase is sensitive to oxygen partial pressure (P_O2). Low laser fluence tends to expand the growth window of pure Sr₂IrO₄ films. The lower P_O2 (≤2.6 Pa) is preferred for preparing Sr₂IrO₄ films, while the SrIrO₃ phase forms at higher P_O2 (≥6.5 Pa). The growth diagram for SrIrO₃ and Sr₂IrO₄ films has been summarized, providing a powerful guideline for fabricating the epitaxial films of single RP-type strontium iridate phase.