[C-8] Spintronics I

[C-8-03] Generation of spin-polarized electrons in n⁺-Si by spin injection through a ferromagnetic tunnel junction: Role of the band diagram

〇Baisen Yu¹, Shoichi Sato^1,2, Masaaki Tanaka^1,2, Ryosho Nakane¹ (1. Univ. of Tokyo (Japan), 2. CSRN (Japan))

Presentation style: On-site (in-person)

https://doi.org/10.7567/SSDM.2022.C-8-03

We studied electron spin polarization in the n+-Si channel of a lateral spin device having Fe-based ferromagnetic tunnel junctions for source and drain electrodes, from both experimentally and theoretically. We proposed an original spin transport model for spin injection/detection polarization (Pinj/ Pdet) by taking into account the band diagram of the ferromagnetic tunnel junction. We demonstrated that our model can explain all the experimental Pinj and Pdet in a wide range of the junction voltage drop. Main findings are as follows: (1) Pinj and Pdet simply originate from the band diagram of the ferromagnetic tunnel junction, namely, spin filtering in the tunnel barrier is not necessary. (2) Pdet is closely related to the electron density near the Si surface facing the tunnel barrier. Our model provides a deep insight into the spin-related physics in Si-based magnetic tunnel junctions.