PREFEX

Project goals

Electronic-structure calculations based on density-functional theory (DFT) have a massive impact on modern materials science. The increasing predictive power of first-principles simulations not only leads to realistic description of materials that improves our understanding of physical and chemical processes, but also opens new possibilities in terms of computational materials discovery. A major reason behind the increasing predictive power of DFT is emerging new advanced exchange-correlation functionals, such as hybrids that combine semilocal DFT with the Fock exchange. It is not clear, however, how precise and reproducible are such calculations performed with state-of-the-art codes. Most frequently, they rely either on pseudopotentials constructed for semilocal DFT or compact basis sets. Furthermore, there are no precise reference data and tools implementing hybrids that can be used efficiently and reliably for testing codes with a periodic boundary conditions. PREFEX will contribute to solving these issues by (i) implementing and showcasing a high-precision and high-performance tool for calculations employing hybrid functionals in the framework of full-potential linearised augmented plane waves, (ii) providing benchmark data that can be used for assessing precision of other electronic structure codes.

People

• Andris Guļāns (project leader)
• Jānis Užulis (doctoral student)
• Dāvis Zavickis (doctoral student)
• Jānis Cīmurs (postdoc)
• Kristiāns Kacars (student assistant)

Completed activities

• A plenary talk at the 79th International Scientific Conference of the University of Latvia (1 February 2021)
• A popular scientific video (in Latvian) at the European Researchers' Night that took place online on 30 April in Latvia
• Participation at the online event/school "exciting news 2021", a prerecorded talk on LAPW
• Published papers:
  • D. Zavickis, K. Kacars, J. Cīmurs, and A. Gulans, Adaptively compressed exchange in the linearized augmented plane wave formalism, Phys. Rev. B 106, 165101 (2022), preprint available via arXiv,
  • J. Užulis, and A. Gulans, Radial Kohn-Sham problem via integral-equation approach, J. Phys. Commun. 6, 085002 (2022), open access.
• Bachelor thesis defended by Kristians Kacars (10 June 2022). Thesis title: "Puasona vienādojuma risināšana elektronu struktūras simulācijās ar dažādu periodiskumu" (Poisson equation solvers in electronic-structure simulations with different periodicities). All obtained data are freely accessible in an open-access repository.
• Poster presentations at the PSI-K 2022 conference (22-25 August 2022):
  • J. Užulis, Radial Kohn-Sham problem via integral-equation approach,
  • D. Zavickis, Adaptively compressed exchange in LAPW.
• Contributed talks at the DPG Spring Meeting of the Condensed Matter Section (SKM) on March 26 - March 31, 2023.
  • K. Kacars, Coulomb potential truncation in hybrid calculations (abstract),
  • D. Zavickis, Adaptively Compressed Exchange in LAPW, (abstract).

Project duration

The project runs from 1 December 2020 until 31 December 2021.

Funding source

PREFEX is funded by the Latvian Council of Science under the grant agreement No. lzp-2020/2-0251.