2D honeycomb transformation into dodecagonal quasicrystals driven by electrostatic forces

This repository contains the key input and output files used for the density fucntional theory calculations of the paper "Mechanism of 2D Oxide Quasicrystal formation from honeycomb structures" by Sebastian Schenk, Oliver Krahn, Eric Cockayne, Holger L. Meyerheim, Marc deBoissieu, Stefan F"orster, and Wolf Widdra (2022).

The calculations were performed using the DFT code VASP, version 5.4.4 [Commercial software is mentioned in this README file to adquately described the procedure. This does not imply an endorsement or recommendation by the National Institute of Standards and Technology, nor that the software used is necessarily the best for the given
purpose.]

The subfolder large_approximant contains the files for the large Sr₄₈Ti₁₃₂O₂₀₄ approximant on a Pt monolayer.  Subfolders honeycomb/Pt_N and sigma/Pt_N contain the files for honeycomb and sigma Ba₈Ti₂₄O₃₆ structures on Pt trilayers with N Pt per layer per periodic cell. Subfolders honeycomb/Pt_N/substrate contain the corresponding files
for the Pt substrate alone.  The honeycomb and sigma structures are at the equilibrium strain as determined by matching interpolated stress results, as described in the Supplementary Information associated with the main Article.

The input files are the standard VASP input files: POSCAR (structure information), POTCAR_TITEL (pseudopotential information. Because the VASP pseudopotential files are proprietary, only the titles of the pseudopotentials used are given), KPOINTS (k-point generation) and INCAR (most calculation details). To accelerate the DFT van der Waals calculation, the file vdw_kernel.bindat from the VASP package (not included here) should also be used.  The output files are OSZICAR (summarizes energy at each iteration) and OUTCAR (full ouput).