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.
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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
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The external libraries
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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
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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
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Last version: rev7 (2021-07-19)
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To obtain a copy of the method patch for VASP release 5.4.4, please contact main authors by email.
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You must have an official VASP license and you must have a valid academic e-mail.
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.
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To compile the SCPC method you should have installed the DL_MG and PSPFFT libraries to solve the poisson equations and the isolate potential.
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For the DL_MG (version 2.1.4), please visit the website https://bitbucket.org/dlmgteam/dl_mg_code_public/src/master/
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For the PSPFFT (1.0.1), please visit the website
- 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.