Questaal Tutorials

The questaal developers have made an extensive set of tutorials to follow. Below I have highlighted the tutorials workshopped at the 2024 workshop hosted at NREL.

Introductory lmf Tutorial

“This tutorial provides a light introduction to running a self-consistent DFT calculation for silicon, using the main density-functional code in the Questaal suite, lmf.”

Introductory QSGW Tutorial

“This tutorial provides a basic demonstration of a quasi-particle self-consistent GW (QSGW) calculation. Theory for GW and QSGW, and its implementation in the Questaal suite, can be found in references 1-5.”

QSGW Tutorial for magnetic bcc Fe

“This tutorial describes how to make a QSGW self-energy, and draw energy bands for elemental Fe, a bcc metal.

Several tutorials build on this one, in particular the tutorial for the dynamical self-energy.”

Making the dynamical GW self energy

“The GW approximation makes a fully nonlocal $\Sigma(k,r,r′,\omega)$, and this tutorial describes how to construct and analyze it. The main utility used to analyze $\Sigma$ is lmfgws. Dynamical Mean Field Theory (DMFT) is a single-site approximation; it thus makes $\Sigma$ nonlocal in time but local in space. However its time-dependence is calculated to a higher level of theory than is done for the GW approximation. The DMFT package generates $\Sigma$ in a different way but, once created, can also use lmfgws to analyze it.”

Extremal points and effective mass

“This tutorial demonstrates how to find extremal points (maxima, minima, and saddle points) in the Brillouin zone, and calculate effective masses using the band-edge utility. LDA silicon was chosen for simplicity, though it is a trivial example as its extremal points are found on high-symmetry lines. band-edge is particularly useful when searching for multiple extremal points, and/or points distinct from those of high symmetry.”