ATAT mcsqs: Create input files for generation of special quasi-random structures (SQS)

SimplySQS: Create special quasi-random structures (SQS) with ATAT mcsqs in interactive interface for input files and output analysis of SQS

If you like the app, please cite: Lebeda, M., Drahokoupil, J., Vlčák, P., Svoboda, Š., & van de Walle, A. (2026). SimplySQS: An automated and reproducible workflow for special quasirandom structure generation with ATAT. Journal of Computational Science, 96, 102846.

Access the application online here: simplysqs.com  (or at https://atat-sqs.streamlit.app/)

Workflow overview

  • Upload crystal structures or retrieved them from implemented search interface in MP, AFLOW, and COD databases.
  • Generate ATAT Input Files: Create rndstr.in and sqscell.out files with global or sublattice-specific composition control. The concentrations are automatically recalculated for the achiavable concentrations given the total number of atoms in supercell.
  • Generate complete bash script that will create the rndstr.in and sqscell.out and run the ATAT mcsqs with improved monitoring and creating the mcsqs_progress.csv
  • Generate complete bash script to automate the SQS search across a range of compositions for a binary alloy system.
  • Convert ATAT Output: Transform bestsqs.out files to VASP, CIF, LAMMPS, and XYZ formats with 3D visualization
  • Monitor Optimization: Analyze ATAT convergence from log files (mcsqs.log or at once for parallel run with mcsqs1.log, mcsqs2.log, …) and CSV time progress file (mcsqs_progress.csv) data with interactive plots and main information. For parallel run, it will automatically identify the best performing optimization
  • Calculate PRDF: Compute Partial Radial Distribution Functions for SQS
  • Create Vacancy Structures: Generate ordered defects by selectively removing specific element from the SQS

Workflow