A thermal diode using phonon rectification

A diode is an element blocking flow in one direction, but letting it pass in the other. The most prominent realization of a diode is an electrical rectifier. In this paper, we demonstrate a thermal diode based on standard silicon processing technology using rectification of phonon transport. We use a recently developed detection method to directly visualize the heat flow through such a device fabricated in a thin silicon membrane. The diode consists of an array of differently shaped holes milled into the membrane by focused ion beam processing. In our experiment, we achieve a rectification ratio of the heat current of 1.7 at a temperature of 150 K.