AX4IIX5IIITe12 (A = Rb, Cs; XII = Mn, Zn, Cd; XIII = Ga, In): quaternary semiconducting tellurides with very low thermal conductivities

The discovery of novel materials with very low thermal conductivity is paramount to improving the efficiency of thermoelectric devices. Here we present a series of quaternary semiconducting tellurides AX(4)(II)X(5)(III)Te(12) (A = Rb, Cs; X-II = Mn, Zn, Cd; X-III = Ga, In) with three-dimensional (3D) diamond-like frameworks (DLFs) and they exhibit a very low thermal conductivity (ca. 0.26-0.42 W m(-1) K-1) around 800 K.