A theoretical study of several fully hydrogenated borophenes.

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.