Yttrium nitride MXenes nanosheets (Yn+1Nn; n=1, 2, 3): Structural stability, electronic, and phonon properties from ab-initio calculations

This study investigates the electronic, structural stability, and phonon properties of Y_n+1N_n MXenes nanosheets (n = 1, 2, and 3) within a honeycomb pattern. The Quantum-Espresso code was used to carry out calculations based on density functional theory (DFT) and the plane wave method. The computational approach involved both the generalized gradient approximation (GGA) and the local density approximation (LDA). Notably, Y₄N₃ was identified as the most stable compound compared to Y₃N₂ and Y₂N variations. Cohesive energy analysis revealed increasing structural stability with increasing n-index, attributed to stronger Y-N bonds in thicker MXene monolayers. Total density of states and band structure calculations demonstrated the metallic behavior of Yn+1Nn within the hexagonal framework. Partial density of states (PDOS) analysis highlighted the significant contribution of Y 4d and N 2p orbitals near the Fermi level to Y-N bonding, which was further confirmed by electron density distribution patterns. Phonon calculations confirmed the dynamic stability of Y_n+1N_n MXenes at ambient pressure, suggesting their potential for experimental synthesis.