Surface modification of titanium carbide MXene monolayers (TiC and TiC) chalcogenide and halogenide atoms

Inspired by the recent successful growth of Ti 2 C and Ti 3 C 2 monolayers, here, we investigate the structural, electronic, and mechanical properties of functionalized Ti 2 C and Ti 3 C 2 monolayers by means of density functional theory calculations. The results reveal that monolayers of Ti 2 C and Ti 3 C 2 are dynamically stable metals. Phonon band dispersion calculations demonstrate that two-surface functionalization of Ti 2 C and Ti 3 C 2 via chalcogenides (S, Se, and Te), halides (F, Cl, Br, and I), and oxygen atoms results in dynamically stable novel functionalized monolayer materials. Electronic band dispersions and density of states calculations reveal that all functionalized monolayer structures preserve the metallic nature of both Ti 2 C and Ti 3 C 2 except Ti 2 C-O 2 , which possesses the behavior of an indirect semiconductor via full-surface oxygen passivation. In addition, it is shown that although halide passivated Ti 3 C 2 structures are still metallic, there exist multiple Dirac-like cones around the Fermi energy level, which indicates that semi-metallic behavior can be obtained upon external effects by tuning the energy of the Dirac cones. In addition, the computed linear-elastic parameters prove that functionalization is a powerful tool in tuning the mechanical properties of stiff monolayers of bare Ti 2 C and Ti 3 C 2 . Our study discloses that the electronic and structural properties of Ti 2 C and Ti 3 C 2 MXene monolayers are suitable for surface modification, which is highly desirable for material property engineering and device integration. Inspired by the recent successful growth of Ti 2 C and Ti 3 C 2 monolayers, here, we investigate the structural, electronic, and mechanical properties of functionalized Ti 2 C and Ti 3 C 2 monolayers with chalcogenide and halogenide atoms by means of density functional theory calculations.