講演情報
[21a-C501-8]Current-induced magneto-optical Kerr effect in topological insulator thin films
〇Shunzhen Wang1, Yukihiro Marui1, Masashi Kawaguchi1, Masamitsu Hayashi1 (1.The Univ. of Tokyo)
キーワード：
orbital current、topological insulator、magneto-optical Kerr effect
Understanding spin accumulation and orbital dynamics in materials is a key issue in modern spintronic research. The magneto-optical Kerr effect (MOKE) has been proposed as a powerful tool for optically detecting spin accumulation and has yielded significant results in semiconductors [1] and metals [2,3]. However, studies on spin accumulation in topological insulator (TI) systems are limited despite their intriguing properties such as insulating bulk states and spin-momentum locked topological surface states (TSS). Therefore, it is crucial to advance our understanding on the underlying mechanisms governing spin and orbital dynamics in TI.
In this work, we investigate current-induced magneto-optical Kerr signal in 3D topological insulator thin films. TI films were fabricated using a two-step deposition method by molecular beam epitaxy (MBE). The growth was in-situ monitored by reflection high-energy electron diffraction (RHEED). The films were then further ex-situ characterized by XRD and Raman spectroscopy. We find the films exhibit excellent surface flatness and single-crystalline nature. The films were subsequently fabricated into Hall bar devices and electrodes are patterned using rf magnetron sputtering and lift-off process. In the measurements, an alternative (AC) current was applied to the sample, and the corresponding Kerr rotation and ellipticity were detected. The magnitude of the observed Kerr signal surpassed that reported in metals. In the presentation, we discuss interpretation of the experimental results.
In this work, we investigate current-induced magneto-optical Kerr signal in 3D topological insulator thin films. TI films were fabricated using a two-step deposition method by molecular beam epitaxy (MBE). The growth was in-situ monitored by reflection high-energy electron diffraction (RHEED). The films were then further ex-situ characterized by XRD and Raman spectroscopy. We find the films exhibit excellent surface flatness and single-crystalline nature. The films were subsequently fabricated into Hall bar devices and electrodes are patterned using rf magnetron sputtering and lift-off process. In the measurements, an alternative (AC) current was applied to the sample, and the corresponding Kerr rotation and ellipticity were detected. The magnitude of the observed Kerr signal surpassed that reported in metals. In the presentation, we discuss interpretation of the experimental results.