Group-IV Pentaoctite: A New 2D Material Family

Abstract

This study investigates the structural, mechanical, and electronic properties of novel two-dimensional (2D) pentaoctite (PO) monolayers composed of group-IV elements (PO-C, PO-Si, PO-Ge, and PO-Sn) using first-principles calculations. Stability is explored through phonon spectra and ab initio molecular dynamics simulations, confirming that all proposed structures are dynamically and thermally stable. Mechanical analysis shows that PO-C monolayers exhibit exceptional rigidity, while the others demonstrate greater flexibility, making them suitable for applications in foldable materials. The electronic properties show semimetallic behavior for PO-C and metallic behavior for PO-Si, while PO-Ge and PO-Sn possess narrow band gaps, positioning them as promising candidates for semiconductor applications. Additionally, PO-C exhibits potential as an efficient catalyst for the hydrogen evolution reaction (HER), with strain engineering further enhancing its catalytic performance. These findings suggest a wide range of technological applications, from nanoelectronics and nanomechanics to metal-free catalysis in sustainable energy production.