Exploring Ferroelectric Field Effect in SrIrO₃ Using First-Principles Calculations

To achieve the ferroelectric (FE) control of metal-insulator transition (MIT) and magnetism in the Ruddlesden-Popper (RP) iridates Sr_n+1Ir_nO_3n+1 (SIO) requires disentangling the complex interplay of electron correlation, spin-orbit coupling, lattice distortion, and symmetry. Here, using first-principles density functional theory calculations on symmetric SrTiO₃/SrIrO₃/PbTiO₃ slabs with different symmetries, thicknesses, electronic correlations, and spin-orbit couplings, we explore MIT and ferroelectric field effects. We find that FE distortions in PbTiO₃ penetrate SrIrO3, shift the electronic band structure with ferroelectric polarization, and may give rise to a thickness-dependent MIT observed in transport measurements, when orthorhombic-type octahedral rotations are considered.