Using first-principles calculations, we found the topological phase transition induced by electric fields in one-bilayer Bi(111). The bandgap decreased with increasing electric field strength, and it is closed at 2.1 V/{\AA}. For fields exceeding 2.1 V/{\AA}, the bandgap increased with increasing electric field strength, reaching 0.34 eV at 4.0 V/{\AA}. We computed the Z2 invariant that characterizes topological insulator phases. As results, one-bilayer Bi(111) showed a topological phase transition induced by the electric field, from the topological insulator phase to the trivial insulator phase through a Dirac semimetal. This topological phase transition could be applied to novel devices.
@article{arxiv.1710.04812,
title = {First-principles study of electric-field-induced topological phase transition in one-bilayer Bi(111)},
author = {Hikaru Sawahata and Naoya Yamaguchi and Hiroki Kotaka and Fumiyuki Ishii},
journal= {arXiv preprint arXiv:1710.04812},
year = {2018}
}