ab-initio study of the structural properties of β12 and χ3 Borophene phases

Abstract
Two-dimensional (2D) materials, characterized by quantum confinement in one dimension (thickness), exhibit unique properties such as high electrical conductivity and mechanical strength, making them a subject of extensive research across multiple scientific disciplines. Among these materials, Borophene—a 2D allotrope of Boron—has emerged as one of the most novel and intriguing nanomaterials. Its exceptional physical and chemical properties, particularly in electronics, spintronics, and energy applications, have drawn significant research interest. Unlike other 2D materials (e.g., graphene), Borophene displays remarkable diversity in its crystalline structures and polymorphs, each exhibiting distinct electronic and mechanical behaviors. Among its many phases, the β₁₂ and χ₃ configurations are among the most stable and technologically relevant. Their structural stability, unique electronic properties, and tunable characteristics under external modifications make them ideal candidates for applications in nanoelectronics and nanophotonics.
In this study, we investigate the structural properties of these two Borophene phases using Quantum ESPRESSO, an open-source computational package based on density functional theory (DFT). Our results reveal a stark contrast in their conductive properties: the β₁₂ phase exhibits semiconducting behavior, whereas the χ₃ phase is metallic. These findings are in close agreement with prior theoretical and experimental studies.