Competition Between Kondo Screening and Magnetism at the LaAlO${}_3$/SrTiO${}_3$ Interface

Abstract

We present a theory of magnetic and magneto-transport phenomena at LaAlO${}_3$/SrTiO${}_3$ interfaces, which as a central ingredient includes coupling between the conduction bands and local magnetic moments originating from charge traps at the interface. Tuning the itinerant electron density in the model drives transitions between a heavy Fermi liquid phase with screened moments and various magnetic states. The dependence of the magnetic phenomena on the electron density or gate voltage stems from competing magnetic interactions between the local moments and the different conduction bands. At low densities only the lowest conduction band, composed of the $d_{xy}$ orbitals of Ti, is occupied. Its antiferromagnetic interaction with the local moments leads to screening of the moments at a Kondo scale that increases with density. However, above a critical density, measured in experiments to be $n_c\approx 1.7\times 10^{13}c{m}^{-2}$, the $d_{xz}$ and $d_{yz}$ bands begin to populate. Their ferromagnetic interaction with the local moments competes with the antiferromagnetic interaction of the $d_{xy}$ band leading to eventual reduction of the Kondo scale with density. We explain the distinct magneto transport regimes seen in experiments as manifestations of the magnetic phase diagram computed from the model. We present new data showing a relation between the anomalous Hall effect and the resistivity in the system. The data strongly suggests that the concentration of local magnetic moments affecting the transport in the system is much lower than the carrier density, in accord with the theoretical model.

13 pages and 9 figures

References in corpus (10)

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• Theory of spin-orbit coupling at LaAlO3/SrTiO3 interfaces and SrTiO3 surfaces
• Oxygen vacancies at titanate interfaces: two-dimensional magnetism and orbital reconstruction
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• Spirals and skyrmions in two dimensional oxide heterostructures
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Cited by in corpus (28)

• Nanoscale Phenomena in Oxide Heterostructures
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• Controlling Kondo-like Scattering at the SrTiO3-based Interfaces
• Anomalous magnetic ground state in LaAlO3/SrTiO3 interface probed by transport through nanowires
• Magnetic interactions at the nanoscale in trilayer titanates LaTiO${}_3$/SrTiO${}_3$/YTiO${}_3$
• Evolution of topological superconductivity by orbital selective confinement in oxide nanowires
• Tuning Rashba spin-orbit coupling at LaAlO3/SrTiO3 interfaces by band filling
• Symmetry and correlation effects on band structure explain the anomalous transport properties of (111) LaAlO${}_3$/SrTiO${}_3$
• Interface exchange processes in LaAlO${}_3$/SrTiO${}_3$ induced by oxygen vacancies
• Oxygen vacancies and hydrogen doping in LaAlO3/SrTiO3 heterostructures: electronic properties and impact on surface and interface reconstruction
• Semiclassical theory of anisotropic transport at LaAlO3/SrTiO3 interfaces under in-plane magnetic field
• Magnetic and nematic orders of the 2DEG at oxide (111) surfaces and interfaces
• Magnetism and electronic structure of YTiO${}_3$ thin films
• The mechanism of spin-orbit coupling in a 2D oxide interface
• Theoretical models of Rashba spin splitting in asymmetric SrTiO3-based heterostructures
• Ferromagnetism and spin-dependent transport at a complex oxide interface
• Ballistic transport through quantum point contacts of multi-orbital oxides
• Spin-orbital polarization of Majorana edge states in oxides nanowires
• Anisotropic Magnetoresistance in Multiband Systems: 2DEGs and Polar Metals at Oxide Interfaces
• Current-induced spin polarization in isotropic k-cubed Rashba model: Theoretical study for p-doped semiconductor heterostructures and perovskite oxides interfaces
• Orbital and spin order in oxide two-dimensional electron gases
• Irreversible multi-band effects and Lifshitz transitions at the LaAlO3/SrTiO3 interface under field effect
• Electric dipole spin resonance in single and two electron quantum dot defined in two-dimensional electron gas at the SrTiO${}_3$/LaAlO${}_3$ interface
• Low temperature magnetoresistance of (111) (La${}_{0.3}$Sr${}_{0.7}$)(Al${}_{0.65}$Ta${}_{0.35}$)/SrTiO${}_3$
• Quantum oscillations in an optically-illuminated two-dimensional electron system at the LaAlO${}_3$/SrTiO${}_3$ interface
• Two-dimensional parabolic Dirac system in the presence of non-magnetic and magnetic impurities
• Fluctuations superconductivity and giant negative magnetoresistance in a gate voltage tuned 2D electron liquid with strong spin-orbit impurity scattering
• Equivalence of magnetic field and particle dilution in the strange metal state of CeCoIn${}_5$