FIRST PRINCIPLE INVESTIGATION OF ROBUSTNESS SURFACE STATES ON TERNARY MIXED CHALCOGENIDE Bi2Te2S

Abstract

In this paper, we present a theoretical investigation on the electronic structures of bulk ternary mixed chalcogenide Bi₂Te₂S and its corresponding Bi₂Te₂S (111) surface thin films based on the first principle within the density-functional theory. The spin-orbit coupling (SOC) included self-consistency. We have found that the effect of SOC significantly changes the electronic properties of bulk Bi₂Te₂S. For the Bi₂Te₂S (111) surface thin films, we have adopted the method proposed by Park K. et al (2010). Our result shows the presence of robustness states on the electronic structure of Bi₂Te₂S (111) thin films with the presence of a Dirac Point (DP) below the Fermi level E_F that is completely covered in the bulk bands. This result is in agreement with the Topological Insulator (TI) nature in the binary Bi₂Te_3.