Dynamics epitaxial stabilization of Sr₃Ir₂O₇ phase in thin film synthesis

Ruddlesden-popper series of Sr_n+1Ir_nO_3n+1 has been a main focus of 5d strong correlated electron systems where the competition between different electronic interactions of similar energy scales has generated a lot of interesting emergent phenomena. With the increasing effective dimensionality within the Sr_n+1Ir_nO_3n+1 series, the ground state evolves from an antiferromagnetic insulating state (Sr₂IrO₄) to a paramagnetic metallic state (SrIrO₃). The small charge gap and collinear antiferromagnetic ordering in Sr₃Ir₂O₇ has made itself a unique playground to study exotic physics near the Mott transition critical point. Tuning electronic and magnetic properties in Sr₃Ir₂O₇ single crystal has resulted in many interesting phenomena, while larger response and more flexibility are expected in Sr₃Ir₂O₇ thin films. However, the synthesis window of Sr₃Ir₂O₇ thin films so far has been limited to a small region. In our research, we have studied the thermal dynamic process of the synthesis of Sr₃Ir₂O₇ thin films under different ambient pressures. In addition, we have found that by changing the ambient pressure through gas mixing the synthesis window for Sr₃Ir₂O₇ can be largely enhanced. This provides a more accessible phase space of epitaxial growth to study the correlated physics in Sr₃Ir₂O₇.