Heavy doped ABA stacked trilayer graphene: triple splitting of its Raman   G peak
  For the first time, we have observed the obvious triple G peak splitting of ABA stacked trilayer graphene. The G peak splitting can be quantatively understood through the different electron-phonon coupling strength of Ea', Eb' and Ea" modes. In addition, the fluctuation of G peak position at different sample locations can also be understood from the view of the varied interaction strength among graphene layers of TLG, which is induced by nonuniform hole doping at the microscopic level. 
S. S. Lin, B. G. Chen, W.Xiong, Y. Yang, L. M. Tong, Y. Xu, J. Luo
cond-mat.mes-hall