Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 41: Spintronics: Excitons and Local Spins (jointly with HL, MA)

TT 41.9: Talk

Tuesday, March 17, 2015, 11:30–11:45, ER 270

DETECTION OF SURFACE SPIN CURRENT IN 3-DIMENSIONAL TOPOLOGICAL INSULATOR, BiSbTeSe — •Masashi Shiraishi¹, Yuichiro Ando¹, Takahiro Hamasaki¹, Kohji Segawa², Satoshi Sasaki², Feng Yang², Mario Novak², and Yoichi Ando² — ¹Kyoto Univ., Japan — ²ISIR, Osaka Univ., Japan

Topological insulators (TIs) attract tremendous attention in recent years, since topologically-protected edge current is a persistent pure spin current. The first detection of the edge current was achieved by using 2-dimensional TI, HgTe quantum well [1], and the next challenge is to detect the edge current in 3-dimensional TIs, because a number of spin channel can be dramatically increased. Whereas Li et al. claimed that they successfully detected the surface spin current in Bi2Se3 by using an electrical spin accumulation method [2], the polarity of the spin signals is not accordance with the direction of magnetization of a detector ferromagnet. Thus, there is still open for discussion how to detect the edge spin current. Here, we present the detection of the edge spin current of BiSbTeSe, which is a bulk insulative TI [3]. The spin signal due to the spin accumulation was detected electrically, and was observed up to 150 K [4].

[1] M. Koenig et al., Science 318, 766 (2007). [2] C. Li et al., Nature Nanotech. 9, 218 (2014). [3] T. Arakane, Yo. Ando et al., Nature Commun. 3, 636 (2011). [4] Yu. Ando, M. Shiraishi et al., Nano Lett., in press.