The proposed scattering geometry is diagrammed. The photoemitted electron is produced upon absorption of circularly polarized light traveling parallel to the long axis of the helix with its spin quantized along the same direction.
The spin-polarization ratio as defined in Eqs. (22) and (44) is plotted for a right-handed helix as a function of the kinetic energy of the incoming particles and the scattering angle . , , , and turns, and the spin-quantization axis is along the helix axis . Above, the bare SO coupling is taken, , and below an effective SO coupling is used, . The results for a left-handed helix are identical.
is plotted for a number of different values for the helix pitch . In all plots, , , and . The spin-quantization axis is along the helix axis, and the effective SO coupling is taken to be . In (a), ; in (b), ; in (c), ; in (d), ; in (e), ; in (f), . As the ratio increases, the potential changes from a ring to a helix, and the magnitude of the asymmetry factor increases.
The spin-polarization ratio (integrated over forward scattering angles from to ) is plotted with the same helix parameters as in Fig. 2. The effective SO coupling is taken to be . Although not shown, at higher kinetic energies the plot plateaus.
Article metrics loading...
Full text loading...