Intrinsic low thermal conductivity and optimization of the thermoelectric figure of merit in epitaxial thin films of CrN*

Thermoelectric properties have been measured in single crystal epitaxial thin films of CrN. Combined with ab-initio calculations, we demonstrate that the rock-salt structure of this system has an intrinsic lattice instability similar to the resonant bond state in classic thermoelectric and phase change materials. The optimized figure of merit of CrN reaches zT$\approx$ 0.12 at 300 K, increasing rapidly with temperature. This results are promising for high temperature applications.