Influence of Geometry on Topological Insulator Behavior of Bi(2)Te(3) Nanowires
Bi(2)Te(3) and Bi(2)Se(3) are well known 3D-topological insulators. Thin films made of these materials exhibit metal-like surface states with a Dirac dispersion. In this work the influence of thickness of the thin-film on the surface-state dispersion is investigated. At low film thickness, the surface states couple to each other and a band gap is opened. Dispersion of these states is also impacted by growth conditions, particularly the substrate. Asymmetric growth conditions are simulated and a Rashba-type splitting of the Dirac cones is observed in agreement with experiment. Low film thickness and asymmetric growth conditions together lead to formation of displaced hyperbolas. The Fermi-velocity of the surface states and band-gap are computed as a function of the film thickness. The surface states are spin-polarized with no out-of-plane component and locked perpendicular to the momentum vector. A spin-filter is proposed based on this principle by utilizing two 3-D topological insulators placed together.
Monday, Sept. 9, 2013, 8 a.m. — Tuesday, Sept. 10, 2013, 10 p.m. CT
Austin, TX, United States
Technical conference and networking event for SRC members and students.