東京無限可積分系セミナー

過去の記録 ~10/06次回の予定今後の予定 10/07~

開催情報 土曜日 13:30~16:00 数理科学研究科棟(駒場) 117号室
担当者 神保道夫、国場敦夫、山田裕二、武部尚志、高木太一郎、白石潤一
セミナーURL https://www.ms.u-tokyo.ac.jp/~takebe/iat/index-j.html

2006年12月02日(土)

13:30-14:30   数理科学研究科棟(駒場) 117号室
村上 修一 氏 (東大物工)
Spin Hall effect in metals and in insulators
[ 講演概要 ]
We theoretically predicted that by applying an electric field
to a nonmagnetic system, a spin current is induced in a transverse
direction [1,2]. This is called a spin Hall effect. After its
theoretical predictions on semiconductors [1,2], it has been
extensively studied theoretically and experimentally, partly due
to a potential application to spintronics devices.
In particular, one of the topics of interest is quantum spin
Hall systems, which are spin analogues of the quantum Hall systems.
These systems are insulators in bulk, and have gapless edge states
which carry a spin current. These edge states are characterized
by a Z_2 topological number [3] of a bulk Hamiltonian.
If the topological number is odd, there appear gapless edge states
which carry spin current. In my talk I will briefly review the
spin Hall effect including its experimental results and present
understanding. Then I will focus on the quantum spin Hall systems,
and explain various properties of the Z_2 topological number and
its relation to edge states.
[1] S. Murakami, N. Nagaosa, and S.-C. Zhang, Science 301, 1348 (2003).
[2] J. Sinova et al., Phys. Rev. Lett. 92, 126603 (2004)
[3] C. L. Kane and E. J. Mele, Phys. Rev. Lett. 95, 146802, 226801 (2005)