Topological states in Chevrel phase materials from first principles calculations

Chevrel phase materials form a family of ternary molybdenum chalcogenides with general chemical formula ${A}_{x}{\mathrm{Mo}}_{6}{X}_{8}$ $(A=\text{metal elements},X=\text{chalcogen})$. The variety $A$ atoms makes large number members and leads to many tunable physical properties, such as the superconductivity, thermoelectricity, ionic conductivity. In this work, we have further found various nontrivial band topological states in these by using first-principle calculations. compounds having time-reversal symmetry, ${\text{BaMo}}_{6}{\text{S}}_{8}, {\text{SrMo}}_{6}{\text{S}}_{8}$, ${\text{Mo}}_{6}{\text{S}}_{8}$, are insulators both $R\overline{3}$ $P\overline{1}$ phases, whereas ${\text{EuMo}}_{6}{\text{S}}_{8}$ within ferromagnetic state is an axion insulator trivial one phase. This indicates that change ions can modify potential, lattice distortion, magnetic orders, which offers unique way influence other properties. We hope work stimulate studies find more intriguing phenomena, superconducting Majorana modes.