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 insulator Bi2Se3. 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.
@article{arxiv.1609.01842,
title = {Spin-Polarized Surface Resonances Accompanying Topological Surface State Formation},
author = {Chris Jozwiak and Jonathan A. Sobota and Kenneth Gotlieb and Alexander F. Kemper and Costel R. Rotundu and Robert J. Birgeneau and Zahid Hussain and Dung-Hai Lee and Zhi-Xun Shen and Alessandra Lanzara},
journal= {arXiv preprint arXiv:1609.01842},
year = {2016}
}