[ThA1] III-V Nanostructures: From Spintronics to Advanced Lasers

8:30 AM - 9:00 AM JST(11:30 PM - 12:00 AM UTC)

[ThA1-01 Invited] Epitaxial half-metallic Heusler alloy/III-V compound semiconductor heterostructures for semiconductor spintronic devices

〇Shinya Yamada^1,2,3, Kohei Hamaya^1,2,3 (1. Center for Spintronics Research Network, Graduate School of Engineering Science, The University of Osaka (Japan), 2. Department of Systems Innovation, Graduate School of Engineering Science, The University of Osaka (Japan), 3. Spintronics Research Network Division, Institute for Open and Transdisciplinary Research Initiatives, The University of Osaka (Japan))

For III-V compound semiconductor spintronic devices with high-performance, we develop epitaxial half-metallic Heusler alloy/III-V compound semiconductor heterostructures. By inserting an ultrathin Co layer between cubic Co₂FeAl_xSi_1-x(CFAS) and wurtzite GaN, an epitaxial CFAS/GaN heterostructure can be obtained. CFAS/n⁺-GaN heterojunctions clearly show tunnel conduction with very small rectification and a low resistance-area product of ~3.8 kΩµm², which is several orders of magnitude smaller than those reported in previous work, at room temperature. Using lateral spin-valve devices with the CFAS/n⁺-GaN contacts, we observe nonlocal spin signals and a Hanle effect curve at low temperatures, suggesting pure spin current transport in bulk GaN. The spin transport is observed at up to room temperature, with a high spin polarization of ~0.2 at a low bias voltage less than 2.0 V, paving the way to GaN-based spintronic devices with highly spin-polarized and low-resistance contacts. We will also introduce our recent studies on epitaxial half-metallic Co-based Heusler alloy/GaAs heterostructures for applications to semiconductor spintronic devices.