Raman Spectroscopy of the Doped Topological Insulator (Cu,Ni)xBi2Se3

Abstract This paper presents a study on the lattice dynamics of doped topological insulator (Cu,Ni) x Bi 2 Se 3 single crystals probed using Raman scattering spectroscopy. The single crystals were grown by melting and characterized through X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. The diffraction patterns were indexed within the space group R- 3m and the samples belonged to the rhombohedral layered structure group typical of Bi 2 Se 3 . A Raman scattering study was developed, in which three modes were observed at low frequencies: A 1g 1 , E g 2 and A 1g 2 . The low frequency E g 1 mode, even if theoretically predicted, was not observed. No difference was observed in Raman lines between the pure and (Cu,Ni)-doped samples, indicating that the Cu and Ni are probably intercalated (and not substituted) between the Se layers.