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Title: Controlling the electronic structure of graphene using surface-adsorbate interactions

Hybridization of atomic orbitals in graphene on Ni(111) opens up a large energy gap of ≈2.8eV between nonhybridized states at the K point. Here we use alkali-metal adsorbate to reduce and even eliminate this energy gap, and also identify a new mechanism responsible for decoupling graphene from the Ni substrate without intercalation of atomic species underneath. Using angle-resolved photoemission spectroscopy and density functional theory calculations, we show that the energy gap is reduced to 1.3 eV due to moderate decoupling after adsorption of Na on top of graphene. Calculations confirm that after adsorption of Na, graphene bonding to Ni is much weaker due to a reduced overlap of atomic orbitals, which results from n doping of graphene. Finally, we show that the energy gap is eliminated by strong decoupling resulting in a quasifreestanding graphene, which is achieved by subsequent intercalation of the Na underneath graphene. Furthermore, the ability to partially decouple graphene from a Ni substrate via n doping, with or without intercalation, suggests that the graphene-to-substrate interaction could be controlled dynamically.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Univ. of Colorado and NIST, Boulder, CO (United States)
  2. National Inst. of Standards and Technology (NIST), Boulder, CO (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
  4. Univ. of Kaiserslautern, Kaiserslautern (Germany); Georg-August-Univ. Gottingen, Gottingen (Germany)
Publication Date:
Grant/Contract Number:
FG02-03ER46066; AC02-06CH11357; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 4; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Univ. of Colorado-Boulder, Boulder, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Contributing Orgs:
EMSL, a National scientific user facility at Pacific Northwest National Laboratory (PNNL); the Center for Nanoscale Materials (CNM) at Argonne National Laboratory (ANL); and the National Energy Research Scientific Computing Center (NERSC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1409337
Alternate Identifier(s):
OSTI ID: 1198716