Theoretical Paradigm for Thermal Rectification via Phonon Filtering and Spectral Confinement

Significant thermal rectification has the potential to revolutionize approaches to controlled heat flow and enable breakthrough technologies such as phononic computing. We demonstrate a framework based on phonon population confinement and filtering that has potential to reach rectifications that are an order of magnitude larger than previous literature. With the use of a straightforward modification of the phonon gas model, we illustrate theoretical thermal rectification in a thin film of diamond (1-10 nm) graded to dimensions >1  μm of between 25% and 250%. Utilizing this mechanism for thermal rectification sets the stage for significant development in thermal devices.