Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces

Abstract

There is steadily increasing evidence that the two-dimensional electron gas (2DEG) formed at the interface of some insulating oxides like LaAlO3/SrTiO3 and LaTiO3/SrTiO3 is strongly inhomogeneous. The inhomogeneous distribution of electron density is accompanied by an inhomogeneous distribution of the (self-consistent) electric field confining the electrons at the interface. In turn this inhomogeneous transverse electric field induces an inhomogeneous Rashba spin-orbit coupling (RSOC). After an introductory summary on two mechanisms possibly giving rise to an electronic phase separation accounting for the above inhomogeneity,we introduce a phenomenological model to describe the density-dependent RSOC and its consequences. Besides being itself a possible source of inhomogeneity or charge-density waves, the density-dependent RSOC gives rise to interesting physical effects like the occurrence of inhomogeneous spin-current distributions and inhomogeneous quantum-Hall states with chiral "edge" states taking place in the bulk of the 2DEG. The inhomogeneous RSOC can also be exploited for spintronic devices since it can be used to produce a disorder-robust spin Hall effect.

13 pages, 15 figures

References in corpus (13)

• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• Highly efficient and tuneable spin-to-charge conversion through Rashba coupling at oxide interfaces
• Theory of spin-orbit coupling at LaAlO3/SrTiO3 interfaces and SrTiO3 surfaces
• The Quantum Hall Transition in Real Space: From Localized to Extended States
• Topological phases in a two-dimensional lattice: Magnetic field versus spin-orbit coupling
• Intrinsic instability of electronic interfaces with strong Rashba coupling
• Metal-insulator transition in a quantum wire driven by a modulated Rashba spin-orbit coupling
• Evidence for charge-vortex duality at the LaAlO${}_3$/SrTiO${}_3$ interface
• Inhomogeneous multi-carrier superconductivity at LaXO3/SrTiO3 (X=Al or Ti) oxide interfaces
• Pseudo-gap in tunneling spectra as a signature of inhomogeneous superconductivity in oxide interfaces
• Harper-Hofstadter problem for 2D electron gas with $\mathbf{k}$-linear Rashba spin-orbit coupling
• Edge channel mixing induced by potential steps in an integer quantum Hall system
• Phase separation and long wave-length charge instabilities in spin-orbit coupled systems

Cited by in corpus (6)

• Electronic phase separation: recent progress in the old problem
• Pauli metallic ground-state in Hubbard clusters with Rashba spin-orbit coupling
• Anisotropic Magnetoresistance in Multiband Systems: 2DEGs and Polar Metals at Oxide Interfaces
• Charge and spin conductivity of a two-dimensional electron gas with random Rashba interaction
• Competing electronic states emerging on polar surfaces
• Spin-1/2 operators exactly mapped to spinful canonical Fermi operators present in two bands