Authors: Shingo Kaneta-Takada, Miho Kitamura, Shoma Arai, Takuma Arai, Ryo Okano, Le Duc Anh, Tatsuro Endo, Koji Horiba, Hiroshi Kumigashira, Masaki Kobayashi, Munetoshi Seki, Hitoshi Tabata, Masaaki Tanaka, Shinobu Ohya
Published: 2022-09-26
DOI: 10.1038/s41467-022-33350-5
Source: Full article
AbstractThe two-dimensional electron gas (2DEG) formed at interfaces between SrTiO3(STO) and other oxide insulating layers is promising for use in efficient spin-charge conversion due to the large Rashba spin-orbit interaction (RSOI). However, these insulating layers on STO prevent the propagation of a spin current injected from an adjacent ferromagnetic layer. Moreover, the mechanism of the spin-current flow in these insulating layers is still unexplored. Here, using a strongly correlated polar-metalLaTiO3+δ(LTO) interlayer and the 2DEG formed at the LTO/STO interface in an all-epitaxial heterostructure, we demonstrate giant spin-to-charge current conversion efficiencies, up to ~190 nm, using spin-pumping ferromagnetic-resonance voltage measurements. This value is the highest among those reported for all materials, including spin Hall systems. Our results suggest that the strong on-site Coulomb repulsion in LTO and the giant RSOI of LTO/STO may be the key to efficient spin-charge conversion with suppressed spin-flip scattering. Our findings highlight the hidden inherent possibilities of oxide interfaces for spin-orbitronics applications.