Nuclear spin polarization in the electron spin-flip Raman scattering of singly charged (In,Ga) As/GaAs quantum dots

作者：Debus J^*; Kudlacik D; Sapega V F; Dunker D; Bohn P; Passmann F; Braukmann D; Rautert J; Yakovlev D R; Reuter D; Wieck A D; Bayer M

来源：Physical Review B, 2015, 92(19): 195421.

DOI：10.1103/PhysRevB.92.195421

We study the interplay between the dynamic nuclear spin polarization and resonant spin-flip Raman scattering of the resident electron in an ensemble of singly charged (In,Ga)As/GaAs quantum dots by using a two-color laser excitation scheme. The shift of the electron spin-flip Raman line gives a direct measure of the optically induced Overhauser shift, while the linewidth indicates nuclear spin fluctuations. The dynamic nuclear spin polarization leads only to a reduction in the electron spin splitting induced by wetting-layer excitation that is copolarized with the resonant quantum dot excitation. The respective mechanism of the two-color spin-flip Raman scattering is discussed together with the electron-nuclear hyperfine interaction and Pauli exclusion principle. The temporal evolution of the Overhauser shift further demonstrates a nuclear spin depolarization within several seconds depending strongly on the temperature.

• 出版日期2015-11-20