Self-Consistent Potential Correction Method

Supercell models are often used to calculate the electronic structure of local perturbations from the ideal periodicity in the bulk or on the surface of a crystal or in wires. When the defect or adsorbent is charged, a jellium counter charge is applied to maintain overall neutrality, but the interaction of the artificially repeated charges has to be corrected, both in the total energy and in the one-electron eigenvalues and eigenstates. This becomes paramount in slab or wire calculations, where the jellium counter charge may induce spurious states in the vacuum. We present here a self-consistent potential correction scheme and provide successful tests of it for bulk and slab calculations.

How to cite:

• The main method:

  Mauricio Chagas da Silva, Michael Lorke, Bálint Aradi, Meisam Farzalipour Tabriz, Thomas Frauenheim, Angel Rubio, Dario Rocca, and Peter Deák

  "Self-Consistent Potential Correction for Charged Periodic Systems"

  Phys. Rev. Lett. 126, 076401 – Published 19 February 2021

  https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.076401

• The external libraries

  • Poisson Solver

    "DL_MG: A Parallel Multigrid Poisson and Poisson–Boltzmann Solver for Electronic Structure Calculations in Vacuum and Solution" James C. Womack, Lucian Anton, Jacek Dziedzic, Phil J. Hasnip, Matt I. J. Probert, and Chris-Kriton Skylaris J. Chem. Theory Comput. 2018, 14, 3, 1412–1432

    https://pubs.acs.org/doi/abs/10.1021/acs.jctc.7b01274

  • Isolate Potential

    "Parallel FFT-based Poisson solver for isolated three-dimensional systems" Reuben D.Budiardja and Christian Y.Cardalla Computer Physics Communications Volume 182, Issue 10, October 2011, Pages 2265-2275

    https://doi.org/10.1016/j.cpc.2011.05.014

Getting the SCPC method

Last version: rev7 (2021-07-19)

VASP-5.4.4

• To obtain a copy of the method patch for VASP release 5.4.4, please contact main authors by email.

• You must have an official VASP license and you must have a valid academic e-mail.

VASP-6.2.0

It is already implemented in the official version of VASP-6.2.0.

Note: The version implemented in VASP is an older version of SCPCP probably contains a bug. A patch for the current SPCP is available on request.

External libraries

• To compile the SCPC method you should have installed the DL_MG and PSPFFT libraries to solve the poisson equations and the isolate potential.

• For the DL_MG (version 2.1.4), please visit the website https://bitbucket.org/dlmgteam/dl_mg_code_public/src/master/

• For the PSPFFT (1.0.1), please visit the website

  http://eagle.phys.utk.edu/pspfft/trac/

Recommendations/Notes

• Please note that SCPC cam only provide meaningful results if delta_rho(r), i.e.,the difference between the electron-distributions of the charged and the reference systems decays towards the cell boundary.