[18p-D61-1~21] 10.4 Spintronics in semiconductor, topological material, superconductor, and multiferroics

3:30 PM - 3:45 PM JST(6:30 AM - 6:45 AM UTC)English Presentation

[18p-D61-10] Effect of spin diffusion on spin dynamics under persistent spin helix regime in a GaAs/AlGaAs semiconductor quantum well

〇Koga Akagi¹, Jun Ishihara¹, Sota Yamamoto¹, Yuzo Ohno², Makoto Kohda^1,3,4,5 (1.Grad. Sch. of Eng., Tohoku Univ., 2.Univ. of Tsukuba, 3.CSIS, Tohoku Univ., 4.DEFS, Tohoku Univ., 5.QUARC, QST)

Keywords:

electron spin,persistent spin helix,electron scattering

The spin lifetime is inversely proportional to the spin diffusion constant in the persistent spin helix state. The spin diffusion constant is determined by the electron momentum scattering time and electron-electron (e-e) scattering time. We investigate effects of the two types of electron scattering mechanisms on the spin dynamics in a GaAs quantum well. We modulated e-e scattering time by changing excitation density. We used two samples have same structure but different mobility, and this leads difference of electron momentum relaxation time. The spin dynamics is measured by the time- and spatially resolved magneto-optical Kerr rotation. We investigated the excitation density dependence of spin dynamics in both samples. Spin relaxation is suppressed as the excitation density increases. The e-e scattering time decreases and this leads to the reduction of the spin diffusion constant at high excitation density. We will also discuss the spin-orbit parameters estimated from spin dynamics.