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Title: Bonding between graphene and MoS{sub 2} monolayers without and with Li intercalation

We performed density functional theory (DFT) calculations for a bi-layered heterostructure combining a graphene layer with a MoS{sub 2} layer with and without intercalated Li atoms. Our calculations demonstrate the importance of the van der Waals (vdW) interaction, which is crucial for forming stable bonding between the layers. Our DFT calculation correctly reproduces the linear dispersion, or Dirac cone, feature at the Fermi energy for the isolated graphene monolayer and the band gap for the MoS{sub 2} monolayer. For the combined graphene/MoS{sub 2} bi-layer, we observe interesting electronic structure and density of states (DOS) characteristics near the Fermi energy, showing both the gap like features of the MoS{sub 2} layer and in-gap states with linear dispersion contributed mostly by the graphene layer. Our calculated total DOS in this vdW heterostructure reveals that the graphene layer significantly contributes to pinning the Fermi energy at the center of the band gap of MoS{sub 2}. We also find that intercalating Li ions in between the layers of the graphene/MoS{sub 2} heterostructure enhances the binding energy through orbital hybridizations between cations (Li adatoms) and anions (graphene and MoS{sub 2} monolayers). Moreover, we calculate the dielectric function of the Li intercalated graphene/MoS{sub 2} heterostructure, themore » imaginary component of which can be directly compared with experimental measurements of optical conductivity in order to validate our theoretical prediction. We observe sharp features in the imaginary component of the dielectric function, which shows the presence of a Drude peak in the optical conductivity, and therefore metallicity in the lithiated graphene/MoS{sub 2} heterostructure.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3]
  1. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  2. Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22486396
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANIONS; BINDING ENERGY; CATIONS; CLATHRATES; COMPARATIVE EVALUATIONS; DENSITY FUNCTIONAL METHOD; DENSITY OF STATES; DIELECTRIC MATERIALS; ELECTRONIC STRUCTURE; GRAPHENE; LAYERS; LITHIUM IONS; METALLICITY; MOLYBDENUM SULFIDES; VAN DER WAALS FORCES