Simple model for effective thermal conductivity of bulk nanostructured materials

• An analytic model to predict the effective thermal conductivity is developed.
• The developed model takes into account the orientation of interfaces.
• The effective thermal conductivity is dominated by perpendicular interfaces.
• The model shows a good agreement with computational and experimental data.
• The model can be applied to different structures and materials.

The ability to design and predict effective thermal transport properties in bulk nanostructured materials is becoming increasingly important as the demand for higher performance and higher efficiency electronics and energy conversion devices grows. A tremendous effort has been focused on understanding and improving our ability to predict thermal transport at an individual interface, resulting in new models that account for phonon populations and electron–phonon coupling. Despite the success of this work, there has been no effort to produce a simple analytic model to predict the effective thermal conductivity of bulk materials that include nanoscale features.This paper focuses on applying knowledge of thermal interface resistances to the development of a simple analytic model that can be used for the efficient prediction of effective thermal transport behavior to aid in the design of thermoelectric materials and microelectronic devices. To this end, molecular dynamics simulations are performed to generate an initial model based on the effective thermal conductivity of in-plane and cross-plane superlattices and embedded nanoparticle and nanowire arrays. The model is then validated and generalized by comparing to existing computational and experimental data. Results shows that the effective thermal conductivity calculated from the analytic model agrees well with that of various systems of different materials and geometries, and provides the ability to predict effective system thermal conductivity of these material systems with variable interface area for optimization of thermal transport properties.