C. Jozwiak, J. A. Sobota, K. Gotlieb, A. F. Kemper, C. R. Rotundu, R. J. Birgeneau, Z. Hussain, D. -H. Lee, Z. -X. Shen, and A. Lanzara. Spin-polarized surface resonances accompanying topological surface state formation. Nature Communications, 7, p. 13143, 2016.
Topological insulators host spin-polarized surface states born out of the energetic inversion of
bulk bands driven by the spin-orbit interaction. Here we discover previously unidentified
consequences of band-inversion on the surface electronic structure of the topological
. By performing simultaneous spin, time, and angle-resolved photoemission
spectroscopy, we map the spin-polarized unoccupied electronic structure and identify a
surface resonance which is distinct from the topological surface state, yet shares a similar
spin-orbital texture with opposite orientation. Its momentum dependence and spin texture
imply an intimate connection with the topological surface state. Calculations show these
two distinct states can emerge from trivial Rashba-like states that change topology through
the spin-orbit-induced band inversion. This work thus provides a compelling view of the
coevolution of surface states through a topological phase transition, enabled by the unique
capability of directly measuring the spin-polarized unoccupied band structure.
Bi2Se3, Phase transitions and critical phenomena, Surfaces, interfaces and thin films, Topological insulators
Costel R Rotundu