Ab initio investigation of structural, electronic and magnetic properties of OH-functionalized monolayer CrX2 (X = S, Se, Te)

In this study, density functional theory (DFT) calculations within the generalized gradient approximations (GGA) were employed to investigate the structural and electronic properties of CrX2 (X = S, Se, Te) monolayers in the octahedral (1T) phase using Quantum ESPRESSO. The influence of adsorbed OH groups on these properties was also examined. The calculations reveal that bond lengths, curvatures, and lattice constants increase with increasing chalcogen atomic number (X), while structural stability decreases. Interestingly, OH group adsorption lowers the total energy for all CrX2 monolayers, indicating enhanced stability, with the highest stability observed for configurations with two adsorbed OH groups. Furthermore, the electronic properties were studied by analyzing the band structures of CrX2 monolayers with and without OH groups across non-magnetic, ferromagnetic, and antiferromagnetic states. While pristine monolayers exhibit metallic behavior in all magnetic states, the introduction of OH groups leads to diverse electronic behaviors. Additionally, the stable magnetic phases of the monolayers were determined in the presence and absence of OH groups.