[19p-P1-1~74] 10 Spintronics and Magnetics（Poster）

[19p-P1-69] Thermoelectric Character of Mn doped InAs-GaSb Superlattices

〇Yuki Taketomi¹, Shigeru Kaku¹, Jyunji Yoshino¹ (1.Tokyo Tech, Dep. Phys)

Keywords:spin current,semimetal,dilluted magnetic semiconductor

Generating spin currents is one of the important issue in order to develop spintronics. We think spin polarized semimetal is a promicing material for generating spin current. In semimetal, temperature gradient (-∇T) causes umbipolar diffusion, namely holes and electrons diffuse together from the high temperature part to the low temperature part. If holes and electrons have appropriate spins, spin current could be generated with umbipolar diffusiton. We focus on Mn doped InAs-GaSb superlattices(SLs) as a model system because of its two characteristic features, large spin splitting generated by spd exchange interaction between localized Mn and s or p electrons, and semimetalic band structure caused from its type-II band alignment which means InAs conduction band overlaps GaSb valence band. In this study, we perform electronic structure calculations based on kp perturbation method including spd exchange interaction and spin-orbit interaction, and calculate transport coefficient α and αs based on calculated electronic structure based on Boltzmann transport theory(charge current j and spin current js are expressed as j=σE+α(-∇T), js=σsE+αsS(-∇T) by using transport coefficient of σ,α,σs,αs). It should be noted that, at appropriate Fermi energy, α=0 and αs≠0 are simultaneously fulfilled, which suggests that pure spin current can be taken out from the superlattice system directly.