Topology-Dependent Enhancement of Pyroelectric Property in Nanoarchitected GaN Metamaterials.

Abstract

Pyroelectric materials exhibit spontaneous polarization in response to temperature fluctuations, a phenomenon known as the <i>pyroelectric effect</i>. This study investigates the pyroelectric properties of nanoarchitected gallium nitride (GaN) metamaterials with distinctive topologies, i.e., body-centered cube, octet truss, gyroid, and spinodoid, using molecular dynamics simulations. Our findings reveal a topology-dependent enhancement in the pyroelectric coefficient, primarily affected by the piezoelectric stress constant and thermal expansion coefficient. We demonstrate that decreasing the relative density further enhances the pyroelectric coefficient due to an increased surface-to-volume ratio that enhances the surface effects. Finally, we compute the pyroelectric figures of merit for thermal energy harvesting application, highlighting the superior pyroelectric performance of nanoarchitected GaN metamaterials compared to bulk GaN and GaN nanowires. These results underscore the potential of nanoscale topology engineering in the field of pyroelectricity for realizing next-generation nanogenerators, thermal imaging devices, and self-powered nanosensors.