Structural, magnetic and vibrational properties of BSTS topological insulator

Abstract

We synthesizedBiSbTe1.5Se1.5,BiSbTe2Se1,BiSbTe2.5Se05members of the most bulk-insulating topological insulators family Bi2-xSbxTe3-ySey by modified Bridgeman method for the comparative structural, magnetic and vibrational studies. From the Raman scattering measurements those systems are observed to follow much higher number of lattice vibrational modes than predicted by group theoretical considerations for R¯3m space group corresponding to an ideally random solid-solution situation. We also report temperature independent paramagnetic behavior due to spin helical Dirac Fermions at the surface state. © 2020 American Institute of Physics Inc.. All rights reserved.