The Jülich FLAPW code family: SPEX-FLEUR
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The Spex code

Spex is an independent program and part of the Jülich FLAPW code family.

It gives access to theoretical spectra and quasiparticle properties employing TDDFT and the GW approximation. As it is based on the all-electron FLAPW method, a large variety of materials can be treated. The code was written with a focus on computational efficiency and ease of use.


  • GW, HF, COHSEX, and PBE0 calculations for semiconductors, insulators, and metals
  • RPA total-energy calculations
  • EELS spectra (RPA)
  • Magnetic response (MBPT)
  • Spin-orbit coupling
  • Treatment of spin-polarized systems and (semi)core states
  • Self-energy evaluated with analytic continuation or contour integration
  • Self-consistent GW (HF, COHSEX, PBE0) calculations
  • Wannier support (e.g., Wannier interpolation)
  • Parallelization

Missing Features

  • Non-collinear magnetism (SOC can be included in second variation, though)
  • TDDFT (discontinued)
  • Optical response

Spex is written and maintained by Christoph Friedrich. Contributions by Manfred Niesert, Ersoy Sasioglu, Mathias Müller, Markus Betzinger, Stefan Rost, Anoop Chandran.

Financial support from the Deutsche Forschungsgemeinschaft through the Priority Programm 1145 "Modern and universal first-principles methods for many-electron systems in chemistry and physics" is gratefully acknowledged.

For further questions about Spex contact Symbol - Mail LinkChristoph Friedrich.

Forschungszentrum Jülich, D-52425 Jülich Institute for Advanced Simulation
Institute Quantum Theory of Materials Impressum
Page last modified:
December 19, 2018