Efficient intrinsic spin-to-charge current conversion in an all-epitaxial single-crystal perovskite-oxide heterostructure of La_0.67Sr_0.33MnO₃/LaAlO₃/SrTiO₃

The two-dimensional electron gas formed at the interface between insulating perovskite oxides LaAlO₃ (LAO) and SrTiO₃ (STO) is promising for efficient spin-charge conversion, so-called the (inverse) Edelstein effect (EE). A giant (inverse) EE has been observed in multilayer structures composed of a polycrystalline ferromagnetic layer and LAO/STO; however, the reported temperature dependences of the (inverse) EE are significantly different from each other, and unified understanding of its real mechanism is still lacking. Here, we demonstrate efficient intrinsic spin-to-charge current conversion in an all-epitaxial single-crystal heterostructure of La_0.67Sr_0.33MnO₃/LAO/STO, which can suppress spin scattering and give us an ideal environment to investigate intrinsic spin-charge conversion. With decreasing temperature to 20 K, the spin-to-charge current conversion efficiency is drastically enhanced to +6.7 nm, which is the largest value among those reported for LAO/STO. Our band-structure calculation well reproduces this behavior and predicts further enhancement by controlling the Fermi level position [1].
[1] S. Ohya et al., arXiv:1906.06016.