Abstract
We studied the atomic and electronic structures of ultrathin Bi(111) films grown on by means of angle-resolved photoemission, first-principles calculations, and low-energy electron diffraction. These Bi films were found to be strained due to the influence of the substrate. Accordingly, the band structure is affected and Bi undergoes a topological phase transition; it is shown that the topological invariant in three dimensions switches from (trivial) to (nontrivial or topological). This was clearly confirmed from the change in the surface-state dispersion near the Fermi level. Our discovery offers a method to produce novel topological systems from simple materials.
- Received 26 January 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.227401
© 2012 American Physical Society