Spin Dynamics in Ferromagnet/10-nm-Thick N-Type GaAs Quantum Well Junctions
Xiao-Chen Ji1,2, Chao Shen1,2, Yuan-Jun Wu1,2, Jun Lu1,2, Hou-Zhi Zheng1,2**
1State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 2College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 101408
Abstract：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/in-situ 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–Perel' 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 electron 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.
2017, Vol. 34 
