Surface-state Coulomb repulsion accelerates a metal-insulator transition in topological semimetal nanofilms.

ABSTRACT: The emergence of quantization at the nanoscale, the quantum size effect (QSE), allows flexible control of matter and is a rich source of advanced functionalities. A QSE-induced transition into an insulating phase in semimetallic nanofilms was predicted for bismuth a half-century ago and has regained new interest with regard to its surface states exhibiting nontrivial electronic topology. Here, we reveal an unexpected mechanism of the transition by high-resolution angle-resolved photoelectron spectroscopy combined with theoretical calculations. Anomalous evolution and degeneracy of quantized energy levels indicate that increased Coulomb repulsion from the surface states deforms a quantum confinement potential with decreasing thickness. The potential deformation strongly modulates spatial di

SUBMITTER: Ito S 

PROVIDER: S-EPMC7083614 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature