Regularities Of The Quantum Spin Hall Phase Formation In Three-Dimensional Tetradymite-Like Topological Insulator Thin Films

We present first-principles calculations of electronic structure and topological properties of thin films of tetradymite-like binary, ternary, and quaternary compounds. Two-dimensional topological insulators were found, including two septuple layer films of PbBi2Te4 with large band gap. We demonstrate that the Pb-based thin films inherit Z(2) dependence on the film thickness from the "parent" quintuple-layer compounds. An effective way to induce the topological phase transition in the trivial thin films is proposed that does not require substantial changes in the in-plane lattice parameter and surface crystal structure.