Exploring the impact of van der Waals-corrected exchange-correlation functional on the physical properties of layered GeSe compound

We have investigated the effects of weak interactions on structural, electronic properties with mechanical and dynamical stability on naturally layered alpha-, beta-, and gamma-phases of GeSe compound using first-principles calculations. The structural and elastic results indicated that Grimme method with Becke-Johnson damping function (DFT-D3 (BJ), takes into account the vdW-dispersion energy-correction, have more accuracy than the standard DFT-PBE. Our results show that the layered GeSe in considered phases have a relatively low mechanical property, indicating they are likely to have low thermal conductivity. The electronic band structures indicate that the considered phases are suitable for optoelectronic applications. Additionally, the phonon dispersion curves and phonon density of states indicate strong anharmonic interactions, which could contribute to high thermoelectric performance.