Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session H25: Topological Materials for Conversion between Charge and Spin Currents
2:30 PM–5:30 PM,
Tuesday, March 6, 2018
LACC Room: 403B
Sponsoring Units: GMAG DCMP
Chair: Sadamichi Maekawa, Tohoku Univ
Abstract: H25.00003 : Spin charge interconversion at surfaces of the topological insulator Bi-Sb-Te and the weyl antiferromagnet Mn3Sn*
3:42 PM–4:18 PM
Spin Hall effects are commonly utilized to interconvert between charge and spin currents. As an alternative mechanism for this interconversion, the spin-momentum locking at the Bi (111)/Ag interface  or the at the Dirac surface state of a topological insulator (TI) have recently been used for highly efficient interconversion .
Our recent study on the spin-torque ferromagnetic resonance in TI ((Bi1-xSbx)2Te3)/non-magnetic metal/ferromagnetic-metal tri-layer films in bulk insulating conditions revealed that the interface conversion coefficient qICS (nm-1) from charge to spin currents stayed at a nearly constant large value of about 0.5 nm-1  except for the Dirac point, which is equivalent to the bulk spin Hall angle of about 50% for the quintuple layer thickness of 1 nm.
We also show recently found novel spin Hall effects in a Weyl antiferromagnet Mn3Sn . Th effects exhibit an anomalous sign change in the resulting spin accumulation when its triangularly ordered moments switch orientation. Our observations demonstrate that a novel type of contribution to the SHE (magnetic SHE, MSHE) and the inverse SHE (MISHE) that is absent in nonmagnetic materials can be dominant in some magnetic materials, including antiferromagnets.
First part of presentation is based on the collaboration with R. Yoshimi, A. Tsukazaki, Y. Fukuma, J. Matsuno, K. S. Takahashi, M. Kawasaki, and Y. Tokura. Second part is with T. Tomita, T. Higo, I. Muhammad, S. Nakatsuji, M. Kimata, K. Kondo, H. Chen, A. MacDonald.
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 K. Kondou et al. Nature Physics12, 1027 (2016).
 K. Kuroda, T. Tomita, et al., Nature Materials 16, 1090 (2017).
*This work was supported by Grants-in-Aid for Scientific Research on Innovative Areas “Nano-spin conversion science” (Grant No. 26103002), by CREST (JPMJCR15Q5), Japan Science and Technology Agency
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