Crossover in thermal transport properties of natural, perovskite-structured superlattices

Abstract

Atomic-level simulations are used to analyze the thermal-transport properties of a naturally layered material: the Ruddlesden-Popper phase, formed by interleaving perovskite layers of strontium titanate with strontium oxide rocksalt layers. The thermal conductivity parallel to the plane of structural layering is found to be systematically greater than that perpendicular to the layering. With decreasing number of perovskite blocks in the structure, a transition is seen from the thermal-transport properties of a bulk solid containing interfaces to that of an anisotropic monolithic material. The exact transition point should be temperature dependent and might enable tuning of the thermal conductance properties of the material. © 2009 American Institute of Physics.