Symmetry induced peculiar Rashba effect on thallium adsorbed Si(1Â 1Â 1) surfaces

The geometric symmetry of the surface plays an important role for the spin-orbit-induced spin texture of two-dimensional electronic states. This article reviews the peculiar Rashba spins induced by a C3 symmetry, including the completely spin polarized surface states with the polarization vector oriented perpendicular to the surface, i.e. a direction that is not expected in a typical Rashba system. This review also describes that this peculiar Rashba situation has possibility to suppress backscattering and therefore to greatly improve the efficiency of spin transport, which is an essential issue in the development of high-performance semiconductor spintronic devices.