Calculation Setup for DOS

Before the electronic DOS can be calculated for any surface, the surface must first be optimized to its lowest energy configuration as the surface may reconstruct once it has been cleaved from the bulk. For the purpose of this tutorial, it will start with an already optimized Pd (111) surface, in which the input and output files for the optimization is located (here). In addition, single point energy calculations were performed to ensure convergence with respect to k points and the cutoff energy. All DFT calculations were performed using the following settings 1 2 3 4:

Parameters for VASP

Exchange-Correlation Functional Type Generalized Gradient Approximation (GGA)
Exchange-Correlation Functional Perdew-Burke-Ernzerhof (PBE)
PsuedopotentialProjector Augmented Wave (PAW) Method
K point Grid Monkhorst-Pack

With the optimized Pd surface, a DFT calculation can be setup to determine the electronic DOS of the surface. The POTCAR and KPOINTS input files will be the same as the ones used for the optimization of the surface. The POSCAR will now contain the atom coordinates for the surface after it has been optimized. Below are the tags and values in the INCAR file.

PRECNORMAL
LREALAUTO
VOSKNOWN1
EDIFF1E-05
ALGOVery_Fast
NELM400
ISYM0
ISMEAR2
SIGMA0.2
ISPIN1
ENCUT450
EDIFFG-0.02
NSW0
IBRION1
ISIF2
POTIM0.5
LWAVE.FALSE.
LCHARG.FALSE.
LORBIT10
LVTOT.TRUE.
LDIPOL.TRUE.
IDIPOL3

Without the LORBIT tag, the electronic DOS will not be readily written as a DOSCAR output file to be later analyzed. Once the necessary input files have been collected, the DFT calculation is ready to run.

References

  1. J. P. Perdew, K. Burke, and M. Ernzerhof, “Generalized Gradient Approximation Made Simple,” Phys. Rev. Lett., vol. 77, no. 18, pp. 3865–3868, Oct. 1996. ↩
  2. J. P. Perdew et al., “Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation,” Phys. Rev. B, vol. 46, no. 11, pp. 6671–6687, Sep. 1992. ↩
  3. P. E. Blöchl, “Projector augmented-wave method,” Phys. Rev. B, vol. 50, no. 24, p. 17953, 1994. ↩
  4. H. J. Monkhorst and J. D. Pack, “Special points for Brillouin-zone integrations,” Phys. Rev. B, vol. 13, no. 12, pp. 5188–5192, Jun. 1976. ↩