wannier90.jl

# # Wannierization using Wannier90
#
# DFTK features an interface with the program
# [Wannier90](http://www.wannier.org/),
# in order to compute maximally-localized Wannier functions (MLWFs)
# from an initial self consistent field calculation.
# All processes are handled by calling the routine `run_wannier90`.
#
# !!! warning "No guarantees on Wannier90 interface"
#     This code is at an early stage and has so far not been fully tested.
#     Bugs are likely and we welcome issues in case you find any!
#
# This example shows how to obtain the MLWFs corresponding
# to the first five bands of graphene. Since the bands 2 to 11 are entangled,
# 15 bands are first computed to obtain 5 MLWFs by a disantanglement procedure.

using DFTK
using Unitful
using UnitfulAtomic

d = 10u"Å"
a = 2.641u"Å"  # Graphene Lattice constant
lattice = [a  -a/2    0;
           0  √3*a/2  0;
           0     0    d]

C = ElementPsp(:C, psp=load_psp("hgh/pbe/c-q4"))
atoms     = [C, C]
positions = [[0.0, 0.0, 0.0], [1//3, 2//3, 0.0]]
model  = model_PBE(lattice, atoms, positions)
basis  = PlaneWaveBasis(model; Ecut=15, kgrid=[5, 5, 1])
scfres = self_consistent_field(basis; n_bands=15, tol=1e-8);

# Plot bandstructure of the system

plot_bandstructure(scfres; kline_density=10)

# Now we use the `run_wannier90` routine to generate all files needed by
# wannier90 and to perform the wannierization procedure.
# In Wannier90's convention, all files are named with the same prefix and only differ by
# their extensions. By default all generated input and output files are stored
# in the subfolder "wannier90" under the prefix "wannier" (i.e. "wannier90/wannier.win",
# "wannier90/wannier.wout", etc.). A different file prefix can be given with the
# keyword argument `fileprefix` as shown below.
#
# We now solve for 5 MLWF using wannier90:

using wannier90_jll  # Needed to make run_wannier90 available
run_wannier90(scfres;
              fileprefix="wannier/graphene",
              n_wannier=5,
              num_print_cycles=25,
              num_iter=200,
              ##
              dis_win_max=19.0,
              dis_froz_max=0.1,
              dis_num_iter=300,
              dis_mix_ratio=1.0,
              ##
              wannier_plot=true,
              wannier_plot_format="cube",
              wannier_plot_supercell=5,
              write_xyz=true,
              translate_home_cell=true,
             );

# As can be observed standard optional arguments for the disentanglement
# can be passed directly to `run_wannier90` as keyword arguments.

# delete temporary files:
rm("wannier", recursive=true)