The energy bands in the solid are degenerated because of
the time-reversal symmetry ε(k, ↑)=ε(-k,
↓), and the space-inversion symmetry ε
(k, ↑)=ε(-k,
↑).
However, at solid surfaces, the space-inversion symmetry is broken
and bands are spin-splitted (Fig. 5).
With heavy atoms such as Bi, the Rashba spin splitting
is large with a large Rashba parameter (Fig. 6).
Our group is trying to achieve the spin dependent quantum
interference and the spin filter.
