Spin Dynamics in Ferromagnet/10-nm-Thick N-Type GaAs Quantum Well Junctions

• Published in: 中国物理快报：英文版 no. 11; pp. 65 - 69
• Main Author: 纪晓晨 申超 吴元军 鲁军 郑厚植
• Format: Journal Article
• Language: English
• Published: 2017
• ISSN: 0256-307X; 1741-3540

Spin dynamics in several different types of ferromagnetic metal(FM)/10-nm-thick n-type GaAs quantum well(QW) junctions is studied by means of time-resolved Kerr rotation measurements. Compared with the MnGa/insitu doped 10-nm-thick n-type GaAs QW junction, the spin lifetime of the MnGa/modulation-doped 10-nm-thick n-type GaAs QW junction is shorter by a factor of 5,consistent with the D’yakonov-Pcrel’ spin relaxation mechanism. Meanwhile, compared with the spin lifetime of the MnAs/in-situ doped 10-nm-thick n-type GaAs QW junction, the MnGa/in-situ doped 10-nm-thick n-type GaAs QW junction is of a spin lifetime longer by a factor of 4.2. The later observation is well explained by the Rashba effect in the presence of structure inversion asymmetry, which acts directly on photo-excited eleetron spins. We demonstrate that MnGa-like FM/in-situ doped 10-nm-thick n-type GaAs QW junctions, which possess relatively low interfacial potential barriers, are able to provide long spin lifetimes.