Tunable spin and orbital polarization in SrTiO3-based heterostructures

Abstract

We formulate the effective Hamiltonian of Rashba spin-orbit coupling (RSOC) in $\mathrm{LaAl}{\mathrm{O}}_3/SrTi{\mathrm{O}}_3$ (LAO/STO) heterostructures. We derive analytical expressions of properties, e.g., Rashba parameter, effective mass, band edge energy and orbital occupancy, as functions of material and tunable heterostructure parameters. While linear RSOC is dominant around the $\Gamma$-point, cubic RSOC becomes significant at the higher-energy anti-crossing region. We find that linear RSOC stems from the structural inversion asymmetry (SIA), while the cubic term is induced by both SIA and bulk asymmetry. Furthermore, the SOC strength shows a striking dependence on the tunable heterostructure parameters such as STO thickness and the interfacial electric field which is ascribed to the quantum confinement effect near the LAO/STO interface. The calculated values of the linear and cubic RSOC are in agreement with previous experimental results.

References in corpus (9)

• Magnetic effects at the interface between nonmagnetic oxides
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• 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
• Observation of Inverse Edelstein Effect in Rashba-Split 2DEG between SrTiO3 and LaAlO3 at Room Temperature
• Rashba induced magnetoconductance oscillations in the LaAlO3-SrTiO3 heterostructure
• Current-driven spin orbit field in LaAlO3/SrTiO3 heterostructures
• Spin responses and effective Hamiltonian for the two dimensional electron gas at oxide interface {LaAlO}${}_3$/{SrTiO}${}_3$
• Accumulation, inversion, and depletion layers in SrTiO${}_3$