Strong interface scattering induced low thermal conductivity in Bi-based GeTe/Bi 2 Te 3 superlattice-like materials.

The thermal conductivities of GeTe/Bi 2 Te 3 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/Bi 2 Te 3 superlattice-like materials significantly decrease due to the effects of interfaces and Bi atoms in Bi 2 Te 3 . Our measured results are in line with the theoretical calculations, and reach an extremely low thermal conductivity at 0.162 W mK -1 compared with published work on Ge-Sb(Bi)-Te, indicating the effectiveness of modulating the thermal properties of phase change materials by using Bi-based GeTe/Bi 2 Te 3 superlattice-like materials. Our findings give a calculation method to modify the thermal characteristics of superlattice-like materials and confirm Bi-based GeTe/Bi 2 Te 3 superlattice-like materials as promising candidates for phase change materials with lower thermal conductivity.