Pressure‐Induced Transformation of Electronic Structure and Magnetism in Y ₂ NiIrO ₆ : A First‐Principles Study

Abstract First‐principles calculations were employed to investigate the changes in the crystal structure, electronic structure, and magnetic properties of Y 2 NiIrO 6 by applying chemical pressure and hydrostatic pressure. First, our results demonstrated that applying chemical pressure to Y 2 NiIrO 6 via lanthanide contraction induces significant modifications in its crystal structure. Specifically, in the light rare earth series, the unit cell volume decreased with increasing chemical pressure. Conversely, the heavy rare earth series exhibit distinct and unique changes. Furthermore, the magnetic structure of the doped R 2 NiIrO 6 has undergone significant modification. Second, under applied hydrostatic pressure on Y 2 NiIrO 6 lattice, the unit cell volume exhibited a continuous decrease. Notably, the β angle of the unit cell parameters decreased with increasing pressure up to 25 GPa and subsequently increased with further pressure application beyond 25 GPa. As the pressure increases, the metallic character of Y 2 NiIrO 6 was enhanced, leading to an increase in electrical conductivity. Electrons were observed to shift from O 2− towards Ir 4+ and Y 3+ . Finally, hydrostatic pressure was applied to Pr 2 NiIrO 6 . Our observations indicated that Pr 2 NiIrO 6 responds differently to pressure compared to Y 2 NiIrO 6 . Our research demonstrates that doping lanthanide elements at the A site exerts significant effects on the crystal structure, electronic structure, and magnetic properties of Y 2 NiIrO 6 . Furthermore, the impacts of applying hydrostatic pressure to Y 2 NiIrO 6 and Pr 2 NiIrO 6 exhibit distinct differences. These findings provide valuable guidance for the design of novel double perovskite materials with tailored properties.