Bottom-up strategy: A typical way to create multi-directional auxeticity in Si2O-based layered material

Abstract

Layered auxetic materials have an acute demand for the in-plane negative Poisson's ratio (NPR) due to dimensional restrictions. Yet, it is not yet apparent and developed where the auxeticity in nanomaterials origins from. Aimed at inserting in-plane auxeticity, in this letter, we theoretically propose a series of Si2O-based layer-stacking materials using a bottom-up strategy. As a result of the materials' chemical O absorption, which causes the Pauli repulsion of inter-layer orbits to shift in the direction of the plane, a newly found multi-directional NPR effect is finally realized in II-BK-Si2O. Furthermore, the multilayer structures preserve dispersion of the SL-Si2O while breaking the semi-Dirac semi-metallic conditions and gapped, endowing the materials semiconducting characteristics and strong carrier mobilities. For Si2O-based materials, the aforementioned benefits open up a wide range of application possibilities and research potential.