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+1 N 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, Y 4 N 3 was identified as the most stable compound compared to Y 3 N 2 and Y 2 N 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+1 N n MXenes at ambient pressure, suggesting their potential for experimental synthesis. • This study investigates the structural, dynamical, electronic, and phonon properties of 2D Y n+1 N n MXenes (n = 1, 2, and 3) within a hexagonal structure. • Band structure and total density of states calculations demonstrate the metallic behavior of Y n+1 N n MXenes. • Cohesive energy analysis indicates that these materials exhibit structural stability, which increases with the n-index. • Phonon calculations confirm the presence of a bandgap and the dynamic stability of these materials. • The calculated phonon bandgap ranges are as follows: Y 2 N (175-252 cm −1 ), Y 3 N 2 (240-351 cm −1 ), and Y 4 N 3 (218-281 cm −1 ). Within these gaps, light and heat transmission is inhibited, allowing the material to act as a filter—blocking specific frequencies while permitting others to pass.