TY - JOUR
T1 - Strong magnetophonon resonance induced triple G-mode splitting in graphene on graphite probed by micromagneto Raman spectroscopy
AU - Qiu, Caiyu
AU - Shen, Xiaonan
AU - Cao, Bingchen
AU - Cong, Chunxiao
AU - Saito, Riichiro
AU - Yu, Jingjiang
AU - Dresselhaus, Mildred S.
AU - Yu, Ting
PY - 2013/10/10
Y1 - 2013/10/10
N2 - The resonance between the G-band phonon excitation and Landau level optical transitions in graphene has been systematically studied by micromagneto Raman mapping. In purely decoupled graphene regions on a graphite substrate, eight traces of anticrossing spectral features with G-mode peaks are observed as a function of magnetic fields up to 9 T, and these traces correspond to either symmetric or asymmetric Landau level transitions. Three distinct split peaks of the G mode, named G-, Gi, and G+, are observed at the strong magnetophonon resonance condition corresponding to a magnetic field of ∼4.65 T. These three special modes are attributed to (i) the coupling between the G phonon and the magneto-optical transitions, which is responsible for G+ and G- and can be well described by the two coupled mode model and (ii) the magnetic field-dependent oscillation of the Gi band, which is currently explained by the G band of graphite modified by the interaction with G+ and G-. The pronounced interaction between Dirac fermions and phonons demonstrates a dramatically small Landau level width (∼1.3 meV), which is a signature of the ultrahigh quality graphene obtained on the surface of graphite.
AB - The resonance between the G-band phonon excitation and Landau level optical transitions in graphene has been systematically studied by micromagneto Raman mapping. In purely decoupled graphene regions on a graphite substrate, eight traces of anticrossing spectral features with G-mode peaks are observed as a function of magnetic fields up to 9 T, and these traces correspond to either symmetric or asymmetric Landau level transitions. Three distinct split peaks of the G mode, named G-, Gi, and G+, are observed at the strong magnetophonon resonance condition corresponding to a magnetic field of ∼4.65 T. These three special modes are attributed to (i) the coupling between the G phonon and the magneto-optical transitions, which is responsible for G+ and G- and can be well described by the two coupled mode model and (ii) the magnetic field-dependent oscillation of the Gi band, which is currently explained by the G band of graphite modified by the interaction with G+ and G-. The pronounced interaction between Dirac fermions and phonons demonstrates a dramatically small Landau level width (∼1.3 meV), which is a signature of the ultrahigh quality graphene obtained on the surface of graphite.
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U2 - 10.1103/PhysRevB.88.165407
DO - 10.1103/PhysRevB.88.165407
M3 - Article
AN - SCOPUS:84885766916
VL - 88
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 0163-1829
IS - 16
M1 - 165407
ER -