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

Highlights: • Importance of macroscopic polarization is studied for SnTe to calculate phonon frequency. • All peaks' positions of phonon density of states are nicely matched with the experimental data. • Different thermodynamical quantities are calculated for SnTe. • Proposed a new way of getting surface states for (001) at $\overline{X}$-point, instead of its usual position on the $\overline{\Gamma }$ – $\overline{X}$. • Robustness of surface states are verified in presence of different type of defects. 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.