TBFIT

Tight-binding parameter FITting package (TBFIT*) for Slater-Koster method

Now you can fit your tight-binding parameters via Slatet-Koster method with a very little effort.

TBFIT is a scientific Fortran program for numerical tight-binding parameter fitting mainly based on Slater-Koster scheme and tight-binding calculations for the electronic band structures of given atomic and electronic configurations with a simple input interfaces. Basically TBFIT fits Slater-Koster parameters including scaling factors to your target first-principles band structure. For the fitting algorithm, Levenberg–Marquardt algorithm (implemented by modifying MINPACK library:https://www.mcs.anl.gov/~more/ANL8074a.pdf), Genetic Algorithm (implemented by modifying PIKAIA library:http://www.hao.ucar.edu/modeling/pikaia/pikaia.php), Particle Swarm Optimization (PSO) methods are available.

You can taste how TBFIT works and its capability throughout the Example section. Once you get proper tight-binding parameters, you can also calculate various Berry phase related quantities, such as Berry curvature, Zak phase, Z2 index, Wannier charge center, first Chern numbe. In addition, density of states, eigenstate charge density or wavefunction plot, STM simulations (integerated eigenstate density within certain energy window), band structures for edge/surface geometries, E-field effects, downfolded band structure, and so on.

You do not need to specify all the bond connections, instead, just provide hopping classes (whether it is 1st-, 2nd-, or 3rd-nearest-neighbor hopping) between atomic species and corresponding hopping parameter names in your input file. Then TBFIT automatically set up tight-binding hamiltonian based on your input geometry and tight-binding parameter setup as defined in input interfaces.

In the future release, I will add some routines for the Green function approach to get the surface state (or edge spectrum as well) and the routines for the spin/mirror Chern number evaluation within the given tight-binding parameter and model hamiltonian.

For the details and examples you can find documents that describes the input tags in MANUAL folder and several input/output files in EXAMPLE folder, respectively.

NOTE:

• If you publish the results of TBFIT then please site this github version : Hyun-Jung Kim. Tight-binding parameter fitting package (TBFIT)

* a temporary name

Download

• via git clone:

  git clone https://github.com/Infant83/TBFIT.git