X-functionalized molybdenene monolayers (X = O, F, Al, Si, Cl)

Molybdenene synthesized experimentally is the sole Dirac material with metallic properties so far [Sahu et al., Nat. Nanotechnol. 18, 1430 (2023)], exhibiting a wide array of unique and outstanding properties with potentially extensive applications. However, the free-standing molybdenene structure is not so stable, which highly limits its further exploitation. In this work, we employ density functional theory calculations and ab initio molecular dynamics simulations to investigate molybdenene monolayers functionalized with various elements (X = H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl) at both basal surfaces, aiming at achieving the stable free-standing molybdenene derivatives. By evaluating the energetic, mechanical, dynamical, and thermodynamic properties, we confirm some stable monolayer structures of X-functionalized molybdenene (X = O, F, Al, Si, Cl), which are named as X-Molybdenene. Therefore, our findings stabilize the molybdenene via surface functionalization, which is crucial for future experimental validations and applications.