Effect of temperature on the elastic and thermoacoustic properties of TbX (X = As, Sb, Bi) compounds

In the present investigation, the temperature-dependent elastic, mechanical, thermal and acoustic features of terbium monopnictides (TbX; X [Formula: see text] As, Sb, Bi) in rock-salt (B1) structure have been theoretically investigated. The second-order elastic constants were calculated to assess mechanical stability and anisotropy. Key mechanical parameters — Young’s modulus, shear modulus, bulk modulus, Poisson’s ratio and compressibility — have been evaluated and visualized in 2D and 3D to investigate elastic anisotropy. Ultrasonic velocities (longitudinal, transverse and average), Debye temperature, thermal conductivity and thermal relaxation time were also estimated to understand the phonon transport and acoustic performance of the selected TbX. The results reveal significant thermal sensitivity in elastic and thermomechanical responses, with systematic trends across the pnictogen series. These findings highlight the potential of TbAs, TbSb and TbBi for high-temperature and high-frequency applications, including thermoelectric energy conversion, advanced microelectronics and thermal management systems.