SCALING HYPOTHESIS FOR CORRECTIONS TO TOTAL-ENERGY AND STRESS IN PLANE-WAVE-BASED AB-INITIO CALCULATIONS

We present a technique aimed at preventing plane-wave-based total ener gy and stress calculations from the effect of abrupt changes in basis set size. This scheme relies on the interpolation of energy as a funct ion of the number of plane waves and on a scaling hypothesis that allo ws us to perform the interpolation for a unique reference volume. From a theoretical point of view, the method is compared to those already proposed in the literature, and its more rigorous derivation is emphas ized. From a practical point of view, we illustrate the importance of the correction on different materials (Si, BaTiO3, and He) correspondi ng to different types of bonding, and to different k-point samplings a nd cutoff energies. Then, we compare the different approaches for the calculation of a(0), B-0, and B-0' in bulk silicon.