Strong interface scattering induced low thermal conductivity in Bi-based GeTe/BiTe superlattice-like materials.

The thermal conductivities of GeTe/BiTe superlattice-like materials are calculated based on density functional perturbation theory (DFPT) and measured using a 3ω method. The calculated results show that the lattice thermal conductivity or thermal diffusivity of GeTe/BiTe superlattice-like materials significantly decrease due to the effects of interfaces and Bi atoms in BiTe. Our measured results are in line with the theoretical calculations, and reach an extremely low thermal conductivity at 0.