Ternary compounds based on binary topological insulators as an efficient way for modifying the Dirac cone

The electronic structure of A$^{\rm IV}$B$^{\rm VI}\cdot$A$^{\rm V}_2$B$^{\rm VI}_3$ ternary compounds consisting of seven-layer atomic blocks separated by van der Waals gaps has been theoretically investigated. The YbBi(Sb)$_2$Te$_4$ compounds have been considered, for which a similar atomic structure has been predicted. It has been shown that most compounds based on Group IV elements, as well as YbBi$_2$Te$_4$, are three-dimensional topological insulators. Calculations of the surface electronic structure of MBi$_2$Te$_4$, where M is a Group IV element or Yb, demonstrate the possibility of tuning the Dirac surface conduction state owing to the first element.