Unique Omnidirectional Negative Poisson's Ratio in-Phase Carbon Monochalcogenides

Abstract

Auxetic materials (negative Poisson's ratio) are of exceptional importance for nanomechanical applications. Using first-principles calculations, we propose two-dimensional-phase carbon monochalcogenides (-CS,-CSe, and-CTe) with very strong auxeticity. In contrast to the known two-dimensional materials, we find that Poisson's ratio is negative in all crystal directions. In addition, the-phase carbon monochalcogenides turn out to be direct or quasi-direct bandgap semiconductors with impressive absorption of solar radiation.