Observation of large spin-polarized Fermi surface of a magnetically proximitized semiconductor quantum well

Abstract

Abstract The magnetic proximity effect (MPE) attracts much attention as a promising way for introducing ferromagnetism into a nonmagnetic electron-transport channel. Although the range of MPE is generally limited to the interface, it is extended to several tens of nm in high-quality semiconductor bilayers consisting of a nonmagnetic quantum well (QW) and an underlying ferromagnetic semiconductor (FMS) layer. To elucidate the mechanism of this long-range MPE, it is essential to observe the magnetically proximitized electronic structure of the nonmagnetic semiconductor. Here, by investigating the Shubnikov - de Haas oscillations in nonmagnetic n-type InAs QW / FMS (Ga,Fe)Sb bilayers, we successfully observe the spin-polarized Fermi surface of the InAs QW. The spontaneous spin-splitting energy in the conduction band of the InAs QW reaches 18 meV when applying a negative gate voltage. This large and gate-tunable spin-polarized Fermi surface of a magnetically proximitized InAs QW provides an ideal platform for novel spintronic and topological devices.