Theoretical prediction of topological insulator in ternary rare earth chalcogenides

A different class of three-dimensional topological insulator, ternary rare-earth chalcogenides, is theoretically investigated with ab initio calculations. Based on both bulk band-structure analysis and the direct calculation of topological surface states, we demonstrate that LaBiTe3 is a topological insulator. La can be substituted by other rare earth elements, which provide candidates for novel topological states such as quantum anomalous Hall insulator, axionic insulator, and topological Kondo insulator. Moreover, YBiTe3 and YSbTe3 are found to be normal insulators. They can be used as protecting barrier materials for both LaBiTe3 and Bi2Te3 families of topological insulators for their well-matched lattice constants and chemical composition.