Surface-state Coulomb repulsion accelerates a metal-insulator transition in topological semimetal nanofilms
Year: 2020
Type: article
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 distributions of quantized wave functions, which leads to acceleration of the transition beyond the original QSE picture. This discovery establishes a complete picture of the long-discussed transition and highlights a new class of size effects dominating nanoscale transport in systems with metallic surface states.
Source: Science Advances
Institutions: The Institute for Solid State Physics, The University of Tokyo, The University of Tokyo, Hiroshima University, Research Institute for Synchrotron Radiation Science, Hiroshima University, Chinese Academy of Sciences, Institute of Physics, National Tsing Hua University, National Synchrotron Radiation Research Center, University of Missouri, University of Illinois Urbana-Champaign
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,500
Awards: Study of electronic and spin structure in B20-type 3d transition metal monosilicide, 原子スケールで制御されたトポロジカル電子状態におけるダイナミクスの解明, G3267153198, G5885230769, Coupled Electronic and Lattice Structures in Thin Crystalline Films, Development of novel materials of atomic layers with Dirac fermions for realizing the next-generation ultrafast devices, G8570440878, G8599027097
OpenAlex ID: W2971899614