High-Mobility Magnetic Two-Dimensional Electron Gas in Engineered Oxide Interfaces

Abstract

The engineered interfaces of complex oxides have abundant physical properties and provide a powerful platform for the exploration of fundamental physics and emergent phenomena. In particular, research on the two-dimensional magnetic systems with high mobility remains a long-standing challenge for the discovery of quantum phase and spintronic applications. Here, we introduce a few atomic layers of the delta doping layer at LaAlO3/SrTiO3 interfaces through elaborately controllable epitaxial growth of SrRuO3. After inserting a SrRuO3 buffer layer, the interfaces exhibit a well-defined anomalous Hall effect up to 100 K and their mobility is enhanced by 3 orders of magnitude at low temperatures. More intriguingly, a large unsaturated positive magnetoresistance is created at interfaces. Combining with the density functional theory calculation, we attribute our findings to the electron transfer at interfaces and the magnetic moment of Ru4+ 4d bands. The results pave a way for further research of two-dimensional ferromagnetism and quantum transport in all-oxide systems.

Enhanced Rashba Spin Orbit Coupling and Magnetic Behavior at Oxide Heterointerfaces by Optical Gating

“…the two-band model corresponding to the two-band conduction and the Langevin-type function for the magnetic induced AHE , respectively. In our work, the R xy –H results measured without light can be fitted by the Langevin-type formula, and the formula is the same as that in a previous work . For our light illumination results, we found it is impossible to fit the nonlinear R xy –H well by solely using one of the two formulas.…”

“…In our work, the R xy −H results measured without light can be fitted by the Langevin-type formula, and the formula is the same as that in a previous work. 20 For our light illumination results, we found it is impossible to fit the nonlinear R xy −H well by solely using one of the two formulas. So we here adopt an extended two-band formula, 27…”

“…Such 2DEG shows a lot of significant phenomena, like superconductivity, high carrier mobility, magnetism, Rashba spin–orbit coupling ( SOC ), and sometimes coexistence of them, − forming a complex system of quantum coherence that responds to multiple external stimuli. Among these appealing properties of interfacial 2DEG, the magnetism is a strongly desired one, , as it provides a powerful platform to study the spintronics in all-oxide devices. − To date, there have been many meaningful works to generate magnetic 2DEGs at the interfaces of complex oxides, like to use a magnetic substrate or capping layer, , to introduce magnetic dopants, , or to insert a magnetic buffer layer into the interface. − These works broaden our horizon in condensed matter physics. In the all-oxide interfacial 2DEGs, the most important and irrefutable fingerprint of magnetism is the anomalous Hall effect ( AHE ), which was first reported by Joshua et al and then discussed by many subsequent works. − To manipulate it, many external stimuli, like light, strain, and electric field, can be available choices, − since they have shown their capabilities in adjusting other properties in all-oxide 2DEGs, like magnetoresistance ( MR ), mobility, etc.…”