[15p-PA01-1~58] 10 スピントロニクス・マグネティクス（ポスター）

▲ [15p-PA01-33] First-principles calculation of the persistent spin helix on an OH-terminated diamond surface

〇(D)Hana Pratiwi Kadarisman¹、Naoya Yamaguchi²、Fumiyuki Ishii² (1.Grad.Sch.Nat.Sci.Technol., Kanazawa Univ.、2.NanoMaRi, Kanazawa Univ.)

キーワード：persistent spin helix, diamond, spintronic

The surface termination of semiconductors is a key factor to overcome instability and chemical reactivity due to the dangling bonds. Hydrogen (H)-terminated diamond surfaces become more electrically conductive.^1,2 On the other hand, oxygen (O)-terminated diamond surfaces exhibit nonconductive electrical characteristics.³ Additionally, the roughness of a diamond (111) surface with an O termination tends to be higher.⁴ The OH termination may address concerns of such roughness.⁵ We calculated the effect of the OH termination on the spin splitting on diamond surfaces by using first-principles calculations. Our calculation predicted that the OH-terminated diamond (111) surface exhibits the persistent spin helix (PSH) with a spin-orbit coupling coefficient α_PSH of 14.2 meV・Å. We also calculated the Rashba spin splitting on an H-terminated diamond surface with a Rashba coefficient α_R of 3.6 meV・Å. The α_PSH of an OH-terminated diamond surface is significantly larger than the α_R of an H-terminated one. OH-terminated diamond surfaces with in-plane electric polarization and mirror symmetry may generate a PSH state which is useful for spintronic devices.

References:
1) S. Albin, L. Watkins, Appl. Phys. Lett. 56, 1454 (1990)
2) M. I. Landstrass, K. V. Ravi, Appl. Phys. Lett. 55, 1391 (1989).
3) F. Li, J. Zhang, X. Wang, M. Zhang, H. Wang, Coatings 7, 88 (2017).
4) N. Tokuda, H. Umezawa, S. Ri, K. Yamabe, H. Okushi, S. Yamasaki, Diam. Relat. Mater. 17, 486 (2008).
5) R. Yoshida, D. Miyata, T. Makino, S. Yamasaki, T. Matsumoto, T. Inokuma, N. Tokuda, Appl. Surf. Sci. 458, 222 (2018).