0 Ju n 20 15 Surface Optical and Bulk Acoustic Phonons in the Topological Insulator , Bi 2 Se 2

X iv :1 50 4. 06 68 5v 2 [ co nd -m at .m es -h al l] 1 0 Ju n 20 15 Surface Optical and Bulk Acoustic Phonons in the Topological Insulator, Bi2Se2Te Uditendu Mukhopadhyay, Dipanjan Chaudhuri, Jit Sarkar, Sourabh Singh, Radha Krishna Gopal, Sandeep Tammu, Prashanth C. Upadhya, and Chiranjib Mitra Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India. Laboratory for Electro-Optics Systems, Indian Space Research Organization, Bangalore 560058, India.