DFT Insights into MAX Phase Borides HfAB [A = S, Se, Te] in Comparison with MAX Phase Carbides HfAC [A = S, Se, Te].

In this work, density functional theory (DFT)-based calculations were performed to compute the physical properties (structural stability, mechanical behavior, and electronic, thermodynamic, and optical properties) of synthesized MAX phases HfSB, HfSC, HfSeB, HfSeC, and HfTeB and the as-yet-undiscovered MAX carbide phase HfTeC. Calculations of formation energy, phonon dispersion curves, and elastic constants confirmed the stability of the aforementioned compounds, including the predicted HfTeC. The obtained values of lattice parameters, elastic constants, and elastic moduli of HfSB, HfSC, HfSeB, HfSeC, and HfTeB showed fair agreement with earlier studies, whereas the values of the aforementioned parameters for the predicted HfTeC exhibit a good consequence of B replacement by C.