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Title: Semiconductor-to-Metal Transition and Quasiparticle Renormalization in Doped Graphene Nanoribbons

A semiconductor-to-metal transition in N = 7 armchair graphene nanoribbons causes drastic changes in its electron and phonon system. In this paper, by using angle-resolved photoemission spectroscopy of lithium-doped graphene nanoribbons, a quasiparticle band gap renormalization from 2.4 to 2.1 eV is observed. Reaching high doping levels (0.05 electrons per atom), it is found that the effective mass of the conduction band carriers increases to a value equal to the free electron mass. This giant increase in the effective mass by doping is a means to enhance the density of states at the Fermi level which can have palpable impact on the transport and optical properties. Electron doping also reduces the Raman intensity by one order of magnitude, and results in relatively small (4 cm -1) hardening of the G phonon and softening of the D phonon. This suggests the importance of both lattice expansion and dynamic effects. Finally, the present work highlights that doping of a semiconducting 1D system is strikingly different from its 2D or 3D counterparts and introduces doped graphene nanoribbons as a new tunable quantum material with high potential for basic research and applications.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [8] ;  [8] ;  [9] ;  [10] ;  [1] ;  [11] ;  [1] ;  [3] ;  [1] ;  [3] ;  [1]
  1. Univ. of Cologne (Germany). Inst. of Physics
  2. Univ. of Cologne (Germany). Inst. of Physics; Saint Petersburg State Univ. (Russian Federation); Leibniz Inst. for Solid State and Materials Research (IFW Dresden), Dresden (Germany)
  3. Univ. of California, Berkeley, CA (United States)
  4. Inst. for Research in Fundamental Sciences (IPM), Tehran (Iran). School of Nano Science
  5. Uppsala Univ. (Sweden). Dept. of Physics and Astronomy; Lund Univ. (Sweden). MAX IV Lab.
  6. Lund Univ. (Sweden). MAX IV Lab.
  7. Uppsala Univ. (Sweden). Dept. of Physics and Astronomy
  8. Forschungszentrum Julich (Germany). Peter Grünberg Inst. Inst. for Advanced Simulation
  9. Univ. of Cologne (Germany). Inst. for Theoretical Physics
  10. Univ. of Cologne (Germany). Inst. of Physics; Univ. of Vienna (Austria). Faculty of Physics; Moscow State Univ., Moscow (Russian Federation). Dept. of Materials Science
  11. Helmholtz Center for Materials and Energy, Berlin (Germany). Electron Storage Ring BESSY II
Publication Date:
Grant/Contract Number:
SC0010409; 0939514; 648589; 321319; CRC1238; GR 3708/2-1; 14-13-00747
Type:
Accepted Manuscript
Journal Name:
Advanced Electronic Materials
Additional Journal Information:
Journal Volume: 3; Journal Issue: 4; Journal ID: ISSN 2199-160X
Publisher:
Wiley
Research Org:
Univ. of California, Berkeley, CA (United States); Univ. of Cologne (Germany); Forschungszentrum Juelich (Germany); Lomonosov Moscow State Univ., Moscow (Russian Federation); Uppsala Univ. (Sweden); Lund Univ. (Sweden)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); European Research Council (ERC); German Research Foundation (DFG); Russian Science Foundation; Swedish Research Council (SRC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ARPES; charge transfer doping; graphene; graphene nanoribbons; Raman
OSTI Identifier:
1461116