Importance of macroscopic polarization on vibrational properties and the robust nature of (001) surface states of SnTe

Abstract

Here, we study the importance of macroscopic polarization for explaining the lattice dynamics of SnTe. Along with this, the robustness of (001) surface states is discussed for the practical application of this compound. The long range Coulomb forces using nonanalytical term correction are needed for proper explanation of experimental phonon modes with the Born effective charge's value of ∼5.5 (∼-5.5) for Sn (Te) atom. The peaks' positions of phonon density of states are in good agreement with the experimental observation. The Debye temperature for SnTe is found to be ∼189 K. We have also explored the possibility of protecting the (001) surface states via mirror and time-reversal symmetry. These surface states are expected to be robust against the point and line defects.