Utilizing twin interfaces to reduce lattice thermal conductivity of superlattice

Abstract

Twin interfaces are easily formed in superlattices due to their lower interfacial energy. However, there are relatively few studies on their effect on the thermal conductivity of superlattices, and the conclusions are unclear. In particular, the degree of influence of the presence of twin interfaces on the thermal conductivity is inconsistent. Therefore, the thermal conductivities of silicon/germanium superlattices with twin interfaces were studied by non-equilibrium molecular dynamics simulations. It was found that the twin interface destroys coherent phonon transport, causes phonon localization, and leads a decrease in the thermal conductivity. The degree of influence of the twin interface on the thermal conductivity is strongly dependent on the period length, the system length, and temperature. Furthermore, phonon density of states, phonon participation rate, and spectral heat flow calculations were employed to deduce the phonon transport mechanisms in superlattices with twin interfaces.