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We unravel the evolution of structural, electronic, magnetic, and topological properties of graphene-like pristine, defected, and strained titanium nitride MXene with different functional groups (-F, -O, -H, and -OH) employing first-principles calculations. The formation and cohesive energies reveal their chemical stability. The MAX phase and defect free functionalized MXenes are metallic in nature except for oxygen terminated one, which is 100% spin polarized half-metallic. Additionally, the bare MXene is nearly half-metallic ferromagnet. The spin-orbit coupling significantly influences the bare MXene possessing band inversion. The strain effect sways the Fermi level thereby shifting it toward lower energy state under compression and toward higher energy state under tensile strain in Ti2NH2. These properties are reversed in Ti2N, Ti2NF2, and Ti2N(OH)2. The half-metallic nature changes to semi-metallic under 1% compression and is completely destroyed under 2% compression. In single vacancy defect, the band structure of Ti2NO2 remarkably transforms from half-metallic to semi-conducting (with large band gap of 1.73 eV) in 12.5% Ti, weakly semi-conducting in 5.5% Ti, and topological semi-metal in 12.5% oxygen. The 25% N defect changes the half-metallic to the metallic with certain topological features. Further, the 12.5% Co substitution in Ti2NO2 preserves the half-metallic character, whereas Mn substitution allows to convert half-metallic into weak semi-metallic preserving ferromagnetic character. However, Cr substitution converts half-metallic ferromagnetic to half-metallic anti-ferromagnetic state. The understanding made here on collective structural stability, and magnetic and topological phenomena in novel 2D MXenes open up their possibility in designing them for synthesis and thereby taking to applications.

From first principles electronic structure calculations, we unravel the evolution of structural, electronic, and magnetic properties of pristine, defected, and strained titanium nitride MXene with different functional groups (-F, -O, -H, and -OH). The formation and cohesive energies reveal their chemical stability. The MAX phase and defect free functionalized MXenes are metallic except for oxygen terminated (Ti 2 NO 2 ) one which is 100% spin polarized half-metallic ferromagnet. The spin-orbit coupling significantly influences the bare MXene (Ti 2 N) to exhibit Dirac topology and band inversion near the high symmetry directions and Fermi level. The strain effect sways the Fermi level thereby shifting it toward lower energy state under compression and toward higher energy state under tensile strain in Ti 2 NH 2 . The Ti 2 NO 2 exhibits exotic electronic structure and magnetic states not only in pristine but also in strained and defected structures. Its half-metallic nature changes to semi-metallic under 1% compression and it is completely destroyed under 2% compression. In single vacancy defect, its band structure remarkably transforms from half-metallic to semi-conducting with large band gap in 12.5% Ti, weakly semi-conducting in 5.5% Ti, and semi-metallic in 12.5% O. The 25% N defect changes it’s half-metallic characteristic to metallic. Further, the 12.5% Co substitution preserves it’s half-metallic character, whereas Mn substitution allows it to convert half-metallic characteristic into weak semi-metallic characteristic preserving ferromagnetism. However, Cr substitution converts half-metallic ferromagnetic state to half-metallic anti-ferromagnetic state. The understanding made here on collective structural stability, and electronic band structure, and magnetic phenomena in novel 2D Ti 2 N derived MXenes open up their possibility in designing them for synthesis and thereby taking to applications.

From first principles electronic structure calculations, we unravel the evolution of structural, electronic, and magnetic properties of pristine, defected, and strained titanium nitride MXene with different functional groups (-F, -O, -H, and -OH). The formation and cohesive energies reveal their chemical stability. The MAX phase and defect free functionalized MXenes are metallic except for oxygen terminated (Ti 2 NO 2 ) one which is 100% spin polarized half-metallic ferromagnet. The spin-orbit coupling significantly influences the bare MXene (Ti 2 N) to exhibit Dirac topology and band inversion near the high symmetry directions and Fermi level. The strain effect sways the Fermi level thereby shifting it toward lower energy state under compression and toward higher energy state under tensile strain in Ti 2 NH 2 . The Ti 2 NO 2 exhibits exotic electronic structure and magnetic states not only in pristine but also in strained and defected structures. Its half-metallic nature changes to semi-metallic under 1% compression and it is completely destroyed under 2% compression. In single vacancy defect, its band structure remarkably transforms from half-metallic to semi-conducting with large band gap in 12.5% Ti, weakly semi-conducting in 5.5% Ti, and semi-metallic in 12.5% O. The 25% N defect changes it’s half-metallic characteristic to metallic. Further, the 12.5% Co substitution preserves it’s half-metallic character, whereas Mn substitution allows it to convert half-metallic characteristic into weak semi-metallic characteristic preserving ferromagnetism. However, Cr substitution converts half-metallic ferromagnetic state to half-metallic anti-ferromagnetic state. The understanding made here on collective structural stability, and electronic band structure, and magnetic phenomena in novel 2D Ti 2 N derived MXenes open up their possibility in designing them for synthesis and thereby taking to applications.