First study of the structural, electronic, and transport properties of new technetium-based MXenes through DFT calculations

This article presents a comprehensive study of new technetium-based MXenes (Tc n+1 C n , for n = 1 and n = 2), exploring their structural, dynamic, electronic, and thermodynamic properties. These materials, which adopt a 2D hexagonal structure, are analyzed in both the non-magnetic (NM) and ferromagnetic (FM) phases. Cohesion energies show that the NM phase is more stable than the FM phase. Phonon calculations confirm the dynamic stability of these structures. The analysis of the electronic properties reveals their metallic behavior. The study of the thermoelectric properties of the Tc 2 C and Tc 3 C 2 materials highlights interesting metallic behaviors, which vary with temperature. The electrical conductivity of both materials follows similar trends, showing that they maintain good electrical conductivity even at high temperatures. Their thermal conductivities also follow a typical metallic pattern, with linear increases, indicating that free electrons dominate thermal transport and enhance their ability to conduct heat at high temperatures. The evolution of the thermoelectric figure of merit (ZT) reveals interesting performance. The results suggest that these materials offer optimal performance at moderate temperatures, but their thermoelectric efficiency decreases at high temperatures due to the increase in thermal conductivity and the decrease in electron mobility. Our new materials Tc 2 C and Tc 3 C 2 exhibit strong thermoelectric potential at room and intermediate temperatures. They are therefore better suited for thermoelectric applications at moderate temperatures.