[23p-E205-1~18] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

▲ [23p-E205-11] Giant spin-to-charge conversion in an all-epitaxial single-crystal-oxide Rashba LaTiO_3+δ/SrTiO₃ heterostructure

〇(D)Shingo Kaneta¹, Miho Kitamura², Shoma Arai¹, Takuma Arai¹, Ryo Okano¹, Le Duc Anh^1,3,4, Tatsuro Endo¹, Koji Horiba², Hiroshi Kumigashira^2,5, Masaki Kobayashi^1,6, Munetoshi Seki^1,6, Hitoshi Tabata^1,6, Masaaki Tanaka^1,6, Shinobu Ohya^1,3,6 (1.Univ. of Tokyo, 2.KEK, 3.IEI, Univ. of Tokyo, 4.PRESTO, JST, 5.IMRAM, Tohoku Univ., 6.CSRN, Univ. of Tokyo)

Keywords:Spin-to-charge conversion, Two-dimensional electron gas, Oxide heterostructure

The two-dimensional electron gas (2DEG) formed at oxide interfaces, such as LaAlO₃/SrTiO₃ (STO) and AlO_x/STO, has attracted much attention for their extremely large spin-to-charge conversion efficiencies λ_IEE up to ~60 nm due to the large Rashba spin-orbit interaction. 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-metal LaTiO_3+δ (LTO) interlayer and the 2DEG formed at the LTO/STO interface in an all-epitaxial heterostructure, we demonstrate giant λ_IEE up to ~190 nm. The obtained λ_IEE is the highest value among those reported for all materials including metals, semiconductors, and topological systems so far. This highly efficient spin transport/conversion highlights the new hidden inherent possibilities of oxide interfaces for spin-orbitronics applications.