Giant negative magnetoresistance driven by spin-orbit coupling at the LAO/STO interface

Abstract

The LAO/STO interface hosts a two-dimensional electron system that is unusually sensitive to the application of an in-plane magnetic field. Low-temperature experiments have revealed a giant negative magnetoresistance (dropping by 70\%), attributed to a magnetic-field induced transition between interacting phases of conduction electrons with Kondo-screened magnetic impurities. Here we report on experiments over a broad temperature range, showing the persistence of the magnetoresistance up to the 20~K range --- indicative of a single-particle mechanism. Motivated by a striking correspondence between the temperature and carrier density dependence of our magnetoresistance measurements we propose an alternative explanation. Working in the framework of semiclassical Boltzmann transport theory we demonstrate that the combination of spin-orbit coupling and scattering from finite-range impurities can explain the observed magnitude of the negative magnetoresistance, as well as the temperature and electron density dependence.

new updates from feedback and review process. main text: improved discussion of the mechanisms of the MR; a discussion of a rescaling of the MR with a characteristic field B*(n). supplemental: theoretical estimate of the "sweet spot" density and window; effect of an out-of-plane B-field component on the MR; discussion of spin-orbit corrections to Boltzmann transport. 6+4 pages, 4+4 figures

References in corpus (8)

• Magnetic effects at the interface between nonmagnetic oxides
• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Theory of spin-orbit coupling at LaAlO3/SrTiO3 interfaces and SrTiO3 surfaces
• Rashba induced magnetoconductance oscillations in the LaAlO3-SrTiO3 heterostructure
• Intrinsic instability of electronic interfaces with strong Rashba coupling
• Large modulation of the Shubnikov-de Haas oscillations by the Rashba interaction at the LaAlO${}_3$/SrTiO${}_3$ interface
• Spin-Orbit Coupling in LaAlO${}_3$/SrTiO${}_3$ interfaces: Magnetism and Orbital Ordering
• Nernst effect beyond the relaxation-time approximation

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• Rashba interaction and local magnetic moments in a graphene-Boron Nitride heterostructure by intercalation with Au
• Electronic subbands in the a-LaAlO${}_3$/KTaO${}_3$ interface revealed by quantum oscillations in high magnetic fields
• Anisotropic electronic transport of the two-dimensional electron system in Al2O3/SrTiO3 heterostructures
• Van Hove scenario of anisotropic transport in a two-dimensional spin-orbit coupled electron gas in an in-plane magnetic field
• Interplay between singlet and triplet pairings in multi-band two-dimensional oxide superconductors
• Dynamic Modulation of the Transport Properties of the LaAlO3/SrTiO3 Interface Using Uniaxial Strain
• Anisotropic Magnetoresistance in Multiband Systems: 2DEGs and Polar Metals at Oxide Interfaces
• Generalized Design Principles for Hydrodynamic Electron Transport in Anisotropic Metals
• Correlation-Induced Band Competition in SrTiO3/LaAlO3
• Electric dipole spin resonance in single and two electron quantum dot defined in two-dimensional electron gas at the SrTiO${}_3$/LaAlO${}_3$ interface
• Unconventional quantum oscillations and evidence of nonparabolic electronic states in quasi-two-dimensional electron system at complex oxide interfaces
• Spin-Hall Current and Nonlocal Transport in Ferromagnet-Free Multi-band models for SrTiO3-Based Nanodevices in the presence of impurities
• Large positive magnetoconductance in carbon nanoscrolls