SPHInX

h1. Welcome to the SPHInX repository. 

!>{width: 70px; align: bottom;}SPHInX.png! S/PHI/nX is a *C++ library* for materials simulation, mostly electronic-structure theory. It also is a program (sphinx) to perform such simulations using *density-functional theory*, and *k.p theory*. In addition, the package offers dozens of specialized programs (add-ons) for smaller tasks related to setup, analysis, post-processing, and other types of simulations.

!<{width: 70px;}sxaccelerate.jpg! In 2009, the base classes of SPHInX relating to *fundamental programming concepts* (memory handling, string handling, math, io, ...)  have been separated from the physics part, and evolved into the "SxAccelerate":https://gitlab.com/sphinxlib/sxaccelerate library. This powerful library is now used for system administration software, computer games, graph databases, ... There is more about the [[History|history of SPHInX]].

SPHInX is natively supported by "*pyiron*":http://pyiron.org/ , an Integrated Development Environment for Computational Materials Science.!pyiron-log.png!

h1. Features

As a library, SPHInX offers features in multiple areas:

h2. Charged defect corrections !>{width: 300px; }GaAs-vacGa-3-formEnergy.png!

* sxdefectalign ("executable":https://sxrepo.mpie.de/attachments/download/20/sxdefectalign.bz2 "manual":https://sxrepo.mpie.de/attachments/download/21/sxdefectalign-manual.pdf) for point defects in *bulk*, see "PRL *102*, 016402 (2009).":https://doi.org/10.1103/PhysRevLett.102.016402 

* sxdefectalign2d ("executable":https://sxrepo.mpie.de/attachments/download/24/sxdefectalign2d.bz2 "manual":https://sxrepo.mpie.de/attachments/download/26/sxdefectalign2d-manual.pdf) for point defects at *surfaces, interfaces*, and *2D materials*, see "Phys. Rev. B *97*, 205425 (2018).":https://doi.org/10.1103/PhysRevB.97.205425

h2. Geometry optimization

* on-the-fly parameterized BFGS quasi-Newton (ricQN) ("sxextopt executable":https://sxrepo.mpie.de/attachments/download/13/sxextopt.bz2 "manual":https://sxrepo.mpie.de/attachments/download/12/sxextopt-manual.pdf), see "Comp. Mat. Sci. *133*, 71 (2017).":https://dx.doi.org/10.1016/j.commatsci.2017.03.001

* standard BFGS quasi-Newton

h2.  k · p

Oliver Marquardt, Stefan Schulz, Christoph Freysoldt, Sixten Boeck, Tilmann Hickel, Eoin P. O’Reilly, Jörg Neugebauer

_A flexible, plane-wave based *k* · *p* multiband model_

"Optical and Quantum Electronics *44*, 183 (2012).":https://doi.org/10.1007/s11082-011-9506-3

* plane-wave basis set (i.e., periodic-boundary conditions)

* flexible N-band model Hamiltonians configurable via input file

* fully flexible system geometry via material maps

* linear and non-linear interpolation of material parameters

* very efficient preconditioner for minimizer

* strain calculation

h2. Add-ons !>{width: 300px; }quamolResidue.jpg!

* powerful atomic-structure handling for generating and manipulating atomic geometries (rotating, non-trivial multiplying, diffs, patching)

* generate slabs, dislocations, random structure

* Freysoldt-van-de-Walle-Neugebauer charged defect correction scheme (sxdefectalign) in 3D and 2D

* phonons from forces

* electronic-structure post-processing: partial densities (also Tersoff-Hamann STM), total & projected DOS, dipole oscillator strengthes, ELNES, MIES

* optimized atomic orbitals (quamols), see "Phys Rev B *84*, 1 (2011).":https://dx.doi.org/10.1103/PhysRevB.84.085101

* external structure optimizer ("sxextopt executable":https://sxrepo.mpie.de/attachments/download/13/sxextopt.bz2 "manual":https://sxrepo.mpie.de/attachments/download/12/sxextopt-manual.pdf)

* interface to the York GW space-time code

h2. DFT

_The object-oriented DFT program library S/PHI/nX_

S. Boeck, C. Freysoldt, A. Dick, L. Ismer, J. Neugebauer "Comp. Phys. Comm. (182), 2011, 543-554":http://www.sciencedirect.com/science/article/pii/S0010465510003619

* plane-wave basis sets

* norm-conserving pseudopotentials or

* PAW formalism (reads Bloechl's cppaw, VASP, abinit PAW setups)

* LDA, GGA-PBE functionals (PBE0 and HSE hybrids as an experimental feature)

* very robust and fast minimizers

* atomic spin constraints

* DFT+U for molecular orbitals

* generalized dipole correction for charged slabs

h2. "SxAccelerate":https://gitlab.com/sphinxlib/sxaccelerate

!<{width: 70px;}sxaccelerate.jpg! 

* base libraries for "C++ simple & powerful"

* easy to learn thanks to limiting complexity to the 95% daily-use case

* templates for the REALLY useful containers: contiguous arrays, doubly-linked lists, stacks, (math) vectors

* simple & powerful string class

* powerful io format

* timers made simple: define locally, but get numbers in the global output

* math support via linking to FFT & linear algebra libraries, but much simplified interface

* simple macro language for MPI-based loop parallelization

h1. About Us

[[et al|List of Authors]]

h2. Contributing Partners

    * Defect Chemistry and Spectroscopy group    

    "Computational Materials Design Dept.":http://www.mpie.de/2702079/computational_materials_design

    Max-Planck-Institut für Eisenforschung

    Düsseldorf, Germany 

    * "Gemmantics IT-Consulting":http://www.gemmantics.com    

    Erkrath, Germany 

    * "Photonics Theory Group":http://www.tyndall.ie/content/photonics-0    

    Tyndall National Institute,

    Cork, Ireland 

    * " Max Planck Computing and Data Facility (MPCDF)":https://www.mpcdf.mpg.de/

    Garching, Germany