[23p-E205-1~18] 10.4 半導体・トポロジカル・超伝導・強相関スピントロニクス

▼ [23p-E205-1] Spin-split Fermi surface of InAs/(Ga,Fe)Sb nonmagnetic/ferromagnetic bilayer semiconductor heterostructures

〇Harunori Shiratani¹、Kosuke Takiguchi¹、Le Duc Anh^1,2,3、Masaaki Tanaka^1,4 (1.EEIS, The Univ. of Tokyo、2.IEI, The Univ. of Tokyo、3.PRESTO, JST、4.CSRN, The Univ. of Tokyo)

キーワード：semiconductor heterostructure, ferromagnetic semiconductor

In this work, we report the first observation of the spin-split Fermi surface in InAs/(Ga,Fe)Sb bilayers via gate-controlled Shubnikov-de Haas (SdH) oscillations. The sample structure consists of InAs (12nm) / (Ga,Fe)Sb (15nm, Fe 20%) / AlSb (100 nm) / AlAs (10 nm) / GaAs (100 nm) on semi-insulating GaAs (001) substrates (Fig. 1a), on which we formed a field-effect transistor structure. Thanks to the high mobility in the InAs QW, we observe clear SdH oscillations in the conductance σ_xx at various gate voltages V_g (Fig. 1b). The Fourier transformed spectra of the SdH oscillations in the σ_xx – V_g relation show a double-peak feature (F₊ and F₋ in Fig. 1c). Our analysis indicates that these two peaks correspond to the spin-split bands at the Fermi surface of the InAs QW, which is induced by the MPE from (Ga,Fe)Sb and strongly depends on V_g. The spin splitting energy by MPE reaches 18 meV, which is the largest value induced by MPE ever reported, and can be effectively controlled by V_g. Our findings will pave a new way for the development of spintronic devices utilizing MPE