[18p-E216-1~10] 10.4 半導体スピントロニクス・超伝導・強相関

[18p-E216-3] Theoretical understanding of the efficient intrinsic spin-to-charge current conversion in La_0.67Sr_0.33MnO₃/LaAlO₃/SrTiO₃

〇大矢 忍^1,2、荒木 大晴¹、Anh Le Duc¹、金田 真悟¹、関 宗俊^1,2、田畑 仁^1,2、田中 雅明^1,2 (1.東大院工、2.CSRN)

キーワード：エデルシュタイン効果、二次元電子ガス、スピン流電流変換

The two-dimensional-electron gas (2DEG) formed at the interface between perovskite insulating oxides LaAlO₃ (LAO) and SrTiO₃ (STO) is very promising for efficient spin-charge conversion, the so-called (inverse) Edelstein effect (IEE). This interface has the large Rashba spin-orbit interaction, which makes this system very attractive. There have been several reports on the IEE at LAO/STO, but the previous results contradict each other; the conversion signal was clearly observed at 7 K in Ref. [1], while the conversion signal strongly decreased to zero with decreasing temperature in Refs. [2,3]. Previously, we showed a very efficient IEE, which is drastically enhanced with decreasing temperature, with the conversion efficiency (λ_IEE) up to +3.9 nm at 20 K, using a high-quality all-epitaxial single-crystal LaSrMnO₃ (LSMO)/ LaAlO₃ (LAO)/ SrTiO₃ (STO) heterostructure grown via molecular beam epitaxy [4]. This value of λ_IEE is the largest positive value ever reported for LAO/STO. Here, we show that our band-structure calculation can well reproduce this behavior of λ_IEE and predicts further possible enhancement of the IEE by controlling the density and relaxation time τ of the 2DEG [5].
[1] E. Lense et al., Nat. Mater., 15,1261 (2016).
[2] Y. Wang et al., Nano. Lett., 17, 7659 (2017).
[3] Q. Song et al., Sci. Adv. 3, e1602312 (2017).
[4] D. Araki, S. Ohys et al., the 66th JSAP Spring meeting, 11a-M101-7 (2019).
[5] S. Ohya, D. Araki, L. D. Anh, S. Kaneta, M. Seki, H. Tabata, and M. Tanaka, ArXiv:1906.06016.