Confinement of quasi-atomic structures in Ti₂N and Ti₃N₂ MXene Electrides

Metal carbides, nitrides, or carbonitrides of early transition metals, better known as MXenes, possess notable structural, electrical, and magnetic properties. Analyzing electronic structures by calculating structural stability, band structure, density of states, Bader charge transfer, and work functions utilizing first principle calculations, we revealed that titanium nitride Mxenes, namely Ti₂N and Ti₃N₂, have excess anionic electrons in their pseudo-atomic structure inside the crystal lattice, making them MXene electrides. Bulk Ti₃N₂ has competing antiferromagnetic (AFM) and ferromagnetic(FM) configurations with slightly more stable AFM configurations, while the Ti₂N MXene is nonmagnetic. Although Ti₃N₂ favors AFM configurations with hexagonal crystal systems having $6/mmm$ point group symmetry, Ti₃N₂ does not support altermagnetism. The monolayer of the Ti₃N₂ MXene is a ferromagnetic electride. These unique properties of having non-nuclear interstitial anionic electrons in the electronic structure of titanium nitride MXene have not yet been reported in the literature. Density functional theory calculations show TiN is neither an electride, MXene, or magnetic.