2017/02/14 by Mathias Gehlmann, Irene Aguilera, Gustav Bihlmayer +14 · 80 citations
Chemistry · Materials Science · Physics and Astronomy · #2D Materials and Applications #Band gap #Bilayer #Chemical physics #Chemistry #Condensed matter physics #Delocalized electron #Direct and indirect band gaps #Effective mass (spring–mass system) #Electronic band structure #Electronic structure #Graphene research and applications #Heterojunction #MXene and MAX Phase Materials #Materials science #Monolayer #Nanotechnology #Physics #Point reflection #cond-mat.mtrl-sci #van der Waals force
paper · pdf · doi:10.1021/acs.nanolett.7b00627
published in Nano Letters 17(9), 5187-5192 (American Chemical Society)
arxiv created 2017/02/14 · openalex publication_date 2017/07/31 · arxiv updated 2017/10/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
ReS 2 is considered as a promising candidate for novel electronic and sensor applications. The low crystal symmetry of this van der Waals compound leads to a highly anisotropic optical, vibrational, and transport behavior. However, the details of the electronic band structure of this fascinating material are still largely unexplored. We present a momentum-resolved study of the electronic structure of monolayer, bilayer, and bulk ReS 2 using k-space photoemission microscopy in combination with first-principles calculations. We demonstrate that the valence electrons in bulk ReS 2 are—contrary to assumptions in recent literature—significantly delocalized across the van der Waals gap. Furthermore, we directly observe the evolution of the valence band dispersion as a function of the number of layers, revealing the transition from an indirect band gap in bulk ReS 2 to a direct gap in the bilayer and the monolayer. We also find a significantly increased effective hole mass in single-layer crystals. Our results establish bilayer ReS 2 as an advantageous building block for two-dimensional devices and van der Waals heterostructures.