Figure 3: Calculated spin polarizations and weights of the wavefunctions.

(a) Calculated band structure for a free-standing 30-bilayer Bi slab along . The magenta (blue) circles represent the surface state with the spin direction pointing to the [ 1 0] ([1 0]) direction. The size of the circles is proportional to the absolute value of the net spin polarization. (b,c) Calculated spin expectation values and the weights of the even and odd parity components of the wavefunctions for the lower (b) and upper (c) surface states as a function of the wave number along . The dashed line in (b) corresponds to the k₄ point.