Bulk crystalline silicon

Calculations were performed for a cubic simulation cell containing 216 silicon atoms and using pseudopotentials generated according to the method of Troullier and Martins [74]. The kinetic energy cut-off for the basis-set was set at 200 eV and the FFT grid contained $72 \times 72 \times 72$ points. The basis-set contained spherical-waves with angular momentum components up to $\ell=2$, and the support regions were chosen to be centred on the bonds, with one support function per region, so that no unoccupied bands were included in this calculation. The Brillouin zone was sampled using only the $\Gamma$-point. A value of 100 eV was used for the penalty functional prefactor $\alpha$.

Figure 9.1: Convergence of total energy with respect to support region radius.

Figure 9.2: Convergence of total energy with respect to density-kernel cut-off.