材料期刊网

We study the spatial distribution of spin polarization and charge transmission for a T-shaped waveguide formed by gate electrodes on the surface of three-dimensional (3D) topological insulator (TI). We demonstrate that an energy gap depending on waveguide geometry parameters is opened and the spin surface-locking is broken by the electrical confinement on the surface of 3D TI. Using continuous condition for the wavefunctions at boundaries between different regions to determine the scattering coefficients, we find that the waveguide can provide an in-plane spin-polarized electron output. This interesting finding may be useful in further understanding surface states of 3D TI. (C) 2011 American Institute of Physics. [doi:10.1063/1.3650263]