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Diluted Oxide Interfaces with Tunable Ground States
摘要： The metallic interface between two oxide insulators, such as LaAlO3/SrTiO3 (LAO/STO), provides new opportunities for electronics and spintronics. However, due to the presence of multiple orbital populations, tailoring the interfacial properties such as the ground state and metal-insulator transitions remains challenging. Here, an unforeseen tunability of the phase diagram of LAO/STO is reported by alloying LAO with a ferromagnetic LaMnO3 insulator without forming lattice disorder and at the same time without changing the polarity of the system. By increasing the Mn-doping level, x, of LaAl1?xMnxO3/STO (0 ≤ x ≤ 1), the interface undergoes a Lifshitz transition at x = 0.225 across a critical carrier density of nc = 2.8 × 1013 cm?2, where a peak TSC ≈255 mK of superconducting transition temperature is observed. Moreover, the LaAl1?xMnxO3 turns ferromagnetic at x ≥ 0.25. Remarkably, at x = 0.3, where the metallic interface is populated by only dxy electrons and just before it becomes insulating, a same device with both signatures of superconductivity and clear anomalous Hall effect (7.6 × 1012 cm?2 < ns ≤ 1.1 × 1013 cm?2) is achieved reproducibly. This provides a unique and effective way to tailor oxide interfaces for designing on-demand electronic and spintronic devices.
关键词： anomalous Hall effect,2D electron liquid,oxide interfaces,superconductivity,metal-insulator transitions
更新于2025-09-23 15:23:52
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Unusual Electric and Optical Tuning of KTaO <sub/>3</sub> -Based Two-Dimensional Electron Gases with 5d Orbitals
摘要： Controlling electronic processes in low dimension electron system is centrally important for both fundamental and applied researches. While most of the previous works focused on SrTiO3-based two-dimensional electron gases (2DEGs), here we report on a comprehensive investigation in this regard for amorphous-LaAlO3/KTaO3 2DEGs with the Fermi energy ranging from ~13 meV to ~488 meV. The most important observation is the dramatic variation of the Rashba spin-orbit coupling (SOC) as Fermi energy sweeps through 313 meV: The SOC effective field first jumps and then drops, leading to a cusp of ~2.6 T. Above 313 meV, an additional species of mobile electrons emerges, with a 50-fold enhanced Hall mobility. A relationship between spin relaxation distance and the degree of band filling has been established in a wide range. It indicates that the maximal spin precession length is ~70.1 nm and the maximal Rashba spin splitting energy is ~30 meV. Both values are much larger than the previously reported ones. As evidenced by density functional theory calculation, these unusual phenomena are closely related to the distinct band structure of the 2DEGs composed of 5d electrons. The present work further deepens our understanding of perovskite conducting interfaces, particularly those composed of 5d transition metal oxides.
关键词： oxide interfaces,spin-orbital coupling,two-dimensional electron gas,optical gating,gating effect
更新于2025-09-23 15:22:29