Spex Manual

Spex is a computer code based on many-body perturbation theory. It uses the all-electron full-potential linearized augmented plane-wave method (FLAPW), which provides an accurate basis set for all kinds of materials including transition metals, oxides, and even f-electron systems.

Currently Spex can calculate quasiparticle properties (one-shot and self-consistent) using the GW approximation, EELS and optical spectra as well as total energies in the RPA approximation, and spin-wave and optical (experimental) spectra from the Bethe-Salpeter equation, Hubbard U parameters, Wannier interpolation, and more. (TDDFT is implemented but unmaintained at the moment.)

It needs input from a converged DFT calculation, which can be generated by Fleur but also by any other FLAPW-DFT code.

For further questions about the Spex code, write to spex-users@fz-juelich.de

If you use Spex for your research, please cite the following work:

Christoph Friedrich, Stefan Blügel, Arno Schindlmayr, “Efficient implementation of the GW approximation within the all-electron FLAPW method”, Phys. Rev. B 81, 125102 (2010).

Spex is published under the MIT open-source license.

The MIT License (MIT) Copyright (c) 2021 Peter Grünberg Institut, Forschungszentrum Jülich, Germany

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.