Fig. 5: Higher-order Rashba model.
From: Reversal of spin-polarization near the Fermi level of the Rashba semiconductor BiTeCl
a Representative constant-energy contours of the linear and cubic Hamiltonians. b, c Comparison between experiment (measured with p-polarized light) and the cubic Rashba model for the in-plane spin component along Γ-M and Γ-K, respectively. d, e Same, but for the out-of-plane spin component. f, g Quantitative comparison between the experimentally-measured spin-polarization and the results of the third-order Rashba model along Γ-K for in-plane and out-of-plane spins, respectively. Each spin-polarization curve is extracted by integrating an energy window of ±45 meV along the outermost sub-bands, as indicated by the guides to the eye in (c). In addition to the plotted statistical error bars, we estimate a fractional systematic uncertainty in the measured spin-polarization of ±10%. An energy-dependent signal-to-background ratio is incorporated into the model to permit a direct comparison with the data (see Supplementary Note 9).
