講演情報
[8p-E207-1]Composition-controlled ferromagnetism in a new quaternary-alloy ferromagnetic semiconductor (Ga,Al,Fe)Sb
〇Leona Kondo1, Hirotaka Hara1, Le Duc Anh1,2, Masaaki Tanaka1,2 (1.EEIS, Univ. Tokyo, 2.CSRN, Univ. Tokyo)
キーワード：
ferromagnetic semiconductors、Molecular Beam Epitaxy、Magnetic Circular Dichroism
Fe-doped III–V ferromagnetic semiconductors (FMSs) are promising materials because their ferromagnetism can be designed through the electronic structure of the host semiconductor. However, quaternary-alloy Fe-doped III–V FMSs remain largely unexplored, although they could provide a powerful way to tune both magnetism and band alignment by composition. Here, we report the growth and systematic composition control of a new quaternary-alloy FMS, (Ga,Al,Fe)Sb. We grew 30-nm-thick (Ga0.8−xAlxFe0.2)Sb films with 0.08 ≤ x ≤ 0.40 on semi-insulating GaAs(001) substrates by molecular beam epitaxy. In situ RHEED confirmed single-crystalline epitaxial growth over the entire Al composition range. Magnetic circular dichroism spectra showed characteristic features of the zinc-blende-type (Ga,Al)Sb host, and the E1 peak shifted systematically to higher energy with increasing Al content, indicating tunable host band gaps. The Curie temperature, estimated from Arrott plots of MCD–H curves, also changed systematically with Al content. These results establish (Ga,Al,Fe)Sb as a new composition-tunable Fe-doped III–V FMS and demonstrate that Al incorporation provides an effective route to engineer ferromagnetism and band alignment in semiconductor heterostructures.