Mass-related inversion symmetry breaking and phonon self-energy renormalization in isotopically labeled AB-stacked bilayer graphene
Author(s)Araujo, Paulo Antonio Trinidade; Frank, Otakar; Mafra, Daniela Lopes; Fang, Wenjing; Kong, Jing; Dresselhaus, Mildred; Kalbac, Martin; ... Show more Show less
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A mass-related symmetry breaking in isotopically labeled bilayer graphene (2LG) was investigated during in-situ electrochemical charging of AB stacked (AB-2LG) and turbostratic (t-2LG) layers. The overlap of the two approaches, isotopic labeling and electronic doping, is powerful tool and allows to tailor, independently and distinctly, the thermal-related and transport-related phenomena in materials, since one can impose different symmetries for electrons and phonons in these systems. Variations in the system's phonon self-energy renormalizations due to the charge distribution and doping changes could be analyzed separately for each individual layer. Symmetry arguments together with first-order Raman spectra show that the single layer graphene (1LG), which is directly contacted to the electrode, has a higher concentration of charge carriers than the second graphene layer, which is not contacted by the electrode. These different charge distributions are reflected and demonstrated by different phonon self-energy renormalizations of the G modes for AB-2LG and for t-2LG.
Departmentdelete; Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Research Laboratory of Electronics
Nature Publishing Group
Araujo, Paulo T., Otakar Frank, Daniela L. Mafra, Wenjing Fang, Jing Kong, Mildred S. Dresselhaus, and Martin Kalbac. “Mass-Related Inversion Symmetry Breaking and Phonon Self-Energy Renormalization in Isotopically Labeled AB-Stacked Bilayer Graphene.” Sci. Rep. 3 (June 24, 2013).
Final published version