A theoretical study of several fully hydrogenated borophenes

Abstract

Several recently synthesized two dimensional borophene monolayers are almost all metallic with a strong anisotropic character, but their structural instability and the need to explore their novel physical properties are still ongoing issues. We present a detailed study of four fully hydrogenated borophenes (β₁₂, δ₃, δ₅ and α borophanes) by first-principles calculations. According to phonon dispersion relations and ab initio molecular dynamics simulations, δ₃ and δ₅ borophanes are dynamically and thermally stable. The structural, mechanical, and electronic properties of δ₃ and δ₅ borophanes are analyzed. The results indicate that charge transfer from B to H atoms is crucial for the stability of two borophane phases. The HSE06 calculations predict that both δ₃ and δ₅ borophanes are semiconductors with indirect band gaps of 1.51 and 1.99 eV, respectively. These findings indicate that δ₃ and δ₅ borophanes are ideal for applications in nanoelectronics.