arXiv subjects

Ji Soo Lim

Publications and source records attributed to Ji Soo Lim.

2 recordsLinked to original sources

arXiv2026

Interfacial charge-transfer in 3d/5d complex oxide heterostructures

Interfacial charge transfer (ICT) provides a powerful route to engineer electronic phases in correlated oxide heterostructures, yet predictive design principles remain elusive. Here, we systematically investigate superlattices composed of the 5d spin-orbit coupled semimetal SrIrO3 and a series of correlated 3d perovskites (LaMnO3, LaFeO3, LaCoO3, and NdNiO3), thereby establishing a quantitative framework for ICT across 3d/5d interfaces. Combining element-specific x-ray absorption spectroscopy with spatially resolved electron energy loss spectroscopy, a homogeneous electron transfer from the 5d to the 3d layers is directly quantified, reaching up to 0.35 e per unit cell in the cobaltate superlattice. We show that the magnitude of ICT scales linearly with the difference in electronegativity between the transition-metal oxide layers, identifying electronegativity-driven band alignment as the dominant mechanism for ICT. Beyond interfacial doping, we find that strong 3d-5d hybridization induces a complete low-spin to high-spin conversion in the cobaltate layers, demonstrating interface-controlled spin-state engineering without chemical substitution. These results establish electronegativity mismatch as a predictive design parameter for correlated oxide interfaces and provide a materials platform for tailoring band filling, orbital hierarchy, and spin configurations in quantum oxide heterostructures, paving the way towards advanced oxide electronics and next-generation information technologies.

cond-mat.mtrl-sci↗

arXiv2025

Inducing ferromagnetism by structural engineering in a strongly spin-orbit coupled oxide

Magnetic materials with strong spin-orbit coupling (SOC) are essential for the advancement of spin-orbitronic devices, as they enable efficient spin-charge conversion, complex magnetic structures, spin-valley physics, topological phases and other exotic phenomena. 5d transition-metal oxides such as SrIrO3 feature large SOC, but usually show paramagnetic behavior due to broad bands and a low density of states at the Fermi level, accompanied by a relatively low Coulomb repulsion. Here, we unveil ferromagnetism in 5d SrIrO3 thin films grown on SrTiO3 (111). Through substrate-induced structural engineering, a zigzag stacking of three-unit-cell thick layers along the [111] direction is achieved, stabilizing a ferromagnetic state at the interfaces. Magnetotransport measurements reveal an anomalous Hall effect below ~30 K and hysteresis in the Hall conductivity below 7 K, indicating ferromagnetic ordering. X-ray magnetic circular dichroism further supports these results. Theoretical analysis suggests that the structural engineering of the IrO6 octahedral network enhances the density of states at the Fermi level and thus stabilizes Stoner ferromagnetism. This work highlights the potential of structurally engineered 5d oxides for spin-orbitronic devices, where efficient control of SOC-induced magnetic phases by electric currents can lead to lower energy consumption and improved performance in next-generation device technologies.

cond-mat.mtrl-sci↗