The persistent spin helix in the presence of hyperfine interactions
Master thesis
Permanent lenke
http://hdl.handle.net/11250/2562296Utgivelsesdato
2018Metadata
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- Institutt for kjemi [1404]
Sammendrag
We study the effect of hyperfine interaction in the persistent spin helix (PSH) by investigating the nuclear spin pumping caused by non-equilibrium electron spin dynamics. In the first two chapters we rederive, based on already published literature, the PSH diffusion equation and a formalism for calculating the nuclear spin pumping from non-equilibrium electron spin dynamics. To get some useful insight into the procedure we use, and to show that it actually works, we calculate the nuclear spin pumping in a proof of principle setup in chapter 4. The nuclear spin pumping, and its effects, in the PSH is studied in chapter 5. We find that the lowest-order effect of the nuclear spin polarization stabilizes the electron spin structure. Some higher-order contributions introduce higher-order harmonics, which also rotate the spin structure out of the plane of the helix. The stabilizing effect is considerable when 100 % of the nuclei are polarized. However, for a more realistic nuclear spin polarization, the effect is small.