Developers

The development and expansion of Questaal Suite has been led by Mark van Schilfgaarde since its inception. During his time with Ole Andersen’s group at the Max Planck Institute for Solid State Institute (1987-1988), Mark implemented Ole’s new tight-binding formulation of the LMTO-ASA method. This code served as the foundation for the well known Stuttgart LMTO-ASA package, and for many descendants of it, including an ASA-GW code by Aryasetiawan, the original formulation of LDA+U, an early formulation of noncollinear magnetism and of linear response for spin waves, and a the first implementation of exact exchange. Since 2018 Dimitar Pashov has taken over as manager and primary developor of Questaal.

There have been many contributors; a partial list is shown below.

Questaal Developers

Mark van Schilfgaarde (King’s College London) Primary Developer

Dimitar Pashov (King’s College London) Manager of Questaal. Primary developer of the current GW implementation.

Swagata Acharya (Raboud University, Netherlands) Primary developer of the current DMFT implementation.

Michael Methfessel (IHP, Germany) Primary developer of the antecedent to the full-potential package.

Tight Binding

Tony Paxton (King’s College London) Original Developer of the tight-binding package; ASA Downfolding

GW

Takao Kotani (Tottori University, Japan) Primary developer of the original GW package. Professor Kotani maintains his code at github.com/tkotani/ecalj. Questaal and the original code have diverged since then but have many similarities.

Sergei Faleev (IBM Research-Almaden, San Jose) Primary developer of Quasiparticle Self-Consistency in GW, and nonequilibrium Keldysh transport.

Martin Lueders (Daresbury Labs) Original implmentation of an MPI version of the QSGW codes

Brian Cunningham (Queen’s University Belfast) Primary developer of ladder diagrams added to GW by Bethe-Salpeter.

Savio Laricchia (King’s College London) Primary developer of implementation of phonons and the electron-phonon interaction into the GW package

QSGW+DMFT

Lorenzo Sponza (King’s College London) Original developer of a QSGW+DMFT implementation

Paolo Pisanti (King’s College London) Original developer of interface between this package and Rutger’s CTQMC code

Francois Jamet (King’s College London) Implementation of constrained RPA and the interface between this package and TRIQS package for the response function

LDA+U

Walter Lambrecht (Case Western Reserve, Ohio) Added several features to the ASA and full-potential codes, e.g. LDA+U and the optics packages.

Green Functions

Kiril Belashchenko (University of Nebraska) CPA, Spin-Orbit Coupling, in the Green’s function package

Derek Stewart Transmission in the Landauer-Buttiker formalism (layer Green’s function), maintainer of LMSuite website

Hervé Ness (King’s College London) Eigen-modes of propagation in the L/R leads and full scattering S-matrix à la Fisher and Lee (Primary developer).

Fully relativistic Dirac solver

Athanasios Chantis (Editor, Physical Review) Implementation of the fully relativistic Dirac equation into the ASA package, for studying transport

Alena Vishina (King’s College London) Self-consistent fully relativistic Dirac equation; relativistic linear response

Magnetic response

Liqin Ke (Ames Lab, Iowa) magnetic linear response, magnetic symmetry, Empty sphere finder

Optics

Pooya Azarhoosh (King’s College London) Additions to the optics packaged; involved in code dissemination and documentation

Ben Kaube

Website

Lewis Christiansen (Imperial College London) Primary developer of Questaal web site

Scott McKechnie (King’s College London) Electric Fields for Spin orbit coupling; involved in redesign of input system and documentation

Gergely Kantor (King’s College London) Primary developer of Questaal web site