Mechanical response, thermal conductivity and phononic properties of group III-V 2D hexagonal compounds

Two-dimensional hexagonal compounds have gained a lot of attention due to their potential application in energy, photovoltaics, mechanics and optoelectronics. In this work, we investigate the mechanical, thermal and phononic properties of group III-V binary compounds using ab-initio calculations. Pressure and strain dependency are also explored. The four compounds, BN, BP, AlN and AlP, are found to exhibit hyperelastic softening behavior and high interatomic rigidity that is highly desirable in the automotive and aeronautical industries. Besides an anisotropic elastic response that appears in the nonlinear regime and at non-zero pressure, the compounds contract when the temperature increases. The results related to thermal conductivity reveal the potential application of BN in thermal management. However, the high Grüneisen parameter and the high phonon sccatering rate render BP and AlN compounds good candidates for thermoelectric devices.