Data from: Diffuson-driven lattice thermal conductivity in Zintl arsenides: disrupting mass-thermal conductivity relation for high thermoelectric performance

Zintl compounds of the Ca14AlSb11 structure type, especially Yb14MSb11 (M
= Mg, Mn, Zn), have emerged as leading contenders for high-temperature
thermoelectric applications because of their very low thermal conductivity
and excellent electronic properties. In comparison, the lighter
arsenic-based compounds have received less attention, as they are
generally thought to have poor thermoelectric performance due to higher
thermal conductivity. In this study, we synthesized 4 compounds, Eu14MAs11
(M = Mg, Zn, Cd) and Eu14Zn1.2As11, and refined their powder diffraction
patterns using Rietveld refinement. We measured the transport properties
of these compounds to demonstrate that diffuson conduction is common
across these compositions, resulting in a lattice thermal conductivity of
about 0.55 W m-1 K-1 at 298 K and challenging the usual relationship
between mass and lattice thermal conductivity. The combination of low
thermal conductivity and high valley degeneracy enables these materials to
reach impressive thermoelectric performance, with Eu14MgAs11 achieving a
maximum zT of 1.3 at 1250 K.