Structural and Mechanical Properties of NbN Alloyed with Hf, In, and Zr for Orthopedic Applications: A First-Principles Study

The search for biocompatible, non-toxic, and wear-resistant materials for orthopedic implant applications is on the rise. Different materials have been investigated for this purpose, some of which have proved successful. However, one challenge that has proven difficult to overcome is the balance between ductility and hardness of these materials. This study employed ab initio calculations to investigate the structural and mechanical properties of niobium nitride (NbN) alloyed with hafnium, indium, and zirconium, with the aim of improving its hardness. The calculations made use of density function theory within the quantum espresso package’s generalized gradient approximation, with Perdew–Burke–Ernzerhof ultrasoft pseudopotentials in all the calculations. It was found that addition of the three metals led to an improvement in both the shear and Young’s moduli of the alloys compared to those of the NbN. However, both the bulk moduli and the Poisson’s ratios reduced with the introduction of the metals. The Young’s moduli of all the samples were found to be higher than that of bone. The Vickers hardness of the alloys were found to be significantly higher than that of NbN, with that of indium being the highest. The alloys are therefore good for wear-resistant artificial bone implants in ceramic acetabulum, and also in prosthetic heads

Visualization of the interaction dynamics between a two-level atom and a graphene sheet covered by a laser field

This study investigates the detection of two discrete quantum phenomena arising from the interaction between a single two-level atom, SU(1,1)quantum systems, and a graphene membrane in the presence of a laser field. We employ quantum skew information and second-order Rényi entropy as measures to discern non-classicality and entropy, respectively. Two distinct scenarios are considered addressing the system: first, when atomic frequency significantly surpasses laser coupling; second, when the atomic frequency is considerably lower than classical laser coupling. In the former case, both phenomena hinge upon initial preparation conditions for the SU(1,1)coherent cavity, whereas, in the second scenario, the non-classicality and entropy are influenced by the coherent graphene. Notably, we find that the detuning parameter enhances the information of the composite system when the intensities of the coherent cavity and graphene membrane are substantial