講演情報
[14a-K303-6]Probing the spin texture of topological surface states using current-induced magneto-optical Kerr effect
〇(D)Shunzhen Wang1, Ryota Miyazaki1, Yuta Kobayashi1, Masashi Kawaguchi1, Kohji Nakamura2, Masamitsu Hayashi1 (1.The Univ. of Tokyo, 2.Mie Univ.)
キーワード：
spin texture、topological insulator、magneto-optical Kerr effect
Topological insulators (TIs) have attracted considerable attention for their spin-momentum-locked topological surface states (TSS). This unique property has sparked significant effort to exploit the surface states to for electrical manipulation of magnetization of an adjacent magnetic layer. However, majority of the studies on current-induced spin accumulation in TIs rely on spin torque measurements which require attaching a ferromagnetic layer on top of TIs. This may influence the characteristics of the TSS. The magneto-optical Kerr effect (MOKE), which can be used to detect spin (and orbital) accumulation directly, has yielded intriguing results in semiconductors and metals. Studies on current induced spin/orbital accumulation in TIs, however, are limited. Here we use MOKE to study the spin texture of TSS.
3D topological insulator (Bi1-xSbx)2Te3 thin films are grown using molecular beam epitaxy (MBE). Magneto-optical Kerr measurements are performed using a homemade setup. An alternative (AC) current was applied to the sample and the corresponding Kerr rotation and ellipticity signals were detected using a balanced photo-detector. The Kerr signal linearly increases with the current applied to the sample. The magnitude of the Kerr signal was found to be significantly larger than that found in metals. We measure the Kerr signal against the Bi: Sb composition to study the Fermi level dependence of the current induced spin accumulation. In the presentation, we discuss interpretation of the experimental results.
3D topological insulator (Bi1-xSbx)2Te3 thin films are grown using molecular beam epitaxy (MBE). Magneto-optical Kerr measurements are performed using a homemade setup. An alternative (AC) current was applied to the sample and the corresponding Kerr rotation and ellipticity signals were detected using a balanced photo-detector. The Kerr signal linearly increases with the current applied to the sample. The magnitude of the Kerr signal was found to be significantly larger than that found in metals. We measure the Kerr signal against the Bi: Sb composition to study the Fermi level dependence of the current induced spin accumulation. In the presentation, we discuss interpretation of the experimental results.