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.