講演情報
[23p-A201-10]Optical Visualization of Current-Induced Spin Accumulation with Linearly Polarized Light
〇(D)Taiki Nishijima1,2, Ryo Ohshima1,2, Yuichiro Ando1,2, Youichi Yanase2,3, Masashi Shiraishi1,2 (1.Dept. Eng., Kyoto Univ., 2.CSRN, Kyoto Univ., 3.Dept. Phys., Kyoto Univ.)
キーワード：
spin Hall effect、photocurrent、photogalvanic effect
Local spin detection is of paramount importance in spintronics. Optical methods offer an attractive alternative to observe spin accumulation, as they do not require a junction with a ferromagnetic material and allow for simpler device structures. We focus on the magnetic photogalvanic effect (MPGE), which occurs under linear polarization irradiation when time-reversal symmetry and inversion symmetry are simultaneously broken. In this work, we investigated the detection of spin accumulation induced by spin Hall effect in nonmagnetic metals using the MPGE. Linear polarization is focused and scanned onto a Pt channel and its polarization angle is periodically modulated from parallel to orthogonal to the channel direction. A lock-in technique is used to detect angular dependent photovoltage, which is the difference between the channel voltage when the parallel and the orthogonal polarizations are irradiated. Under finite current application, clear signals are found at the edges of the Pt channel, where inversion symmetry is broken and out-of-plane spin accumulation by SHE is present. The sign change of the angular dependent photovoltage between positive and negative current applications is explained by the reversal of the direction of the accumulated spins. After the 90° rotation of the channel direction, the sign also reversed. These results are consistent with the symmetry of MPGE indicating successful detection of spin accumulation.