.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "gallery/wannier.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_gallery_wannier.py>`
        to download the full example code

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_gallery_wannier.py:


====================================
Wannier tight binding band structure
====================================

.. GENERATED FROM PYTHON SOURCE LINES 7-18

.. code-block:: Python

    # sphinx_gallery_thumbnail_number = 2

    import numpy as np
    from fplore import FPLORun
    import matplotlib.pyplot as plt
    from fplore.util import linspace_ng


    tbrun = FPLORun("../example_data/ReO3/wannier/")
    ham = tbrun['+hamdata']








.. GENERATED FROM PYTHON SOURCE LINES 19-20

Set up the k-path

.. GENERATED FROM PYTHON SOURCE LINES 20-32

.. code-block:: Python


    G = (0, 0, 0)
    X = (1, 0, 0)
    M = (1, 1, 0)
    R = (1, 1, 1)
    k = np.vstack([linspace_ng(G, X),
                   linspace_ng(X, M),
                   linspace_ng(M, R),
                   linspace_ng(R, G),
                   ])
    k = k * np.pi / ham.lattice_vectors[0, 0]








.. GENERATED FROM PYTHON SOURCE LINES 33-34

Plot the tight binding band structure.

.. GENERATED FROM PYTHON SOURCE LINES 34-53

.. code-block:: Python


    H = np.zeros((len(k), ham.nwan, ham.nwan), dtype=np.cdouble)
    for (i, j), hopping in ham.data.items():
        H[..., i, j] = (np.exp(1j * np.dot(k, hopping['T'].T)) * hopping['H']).sum(axis=-1)
        H[..., j, i] = H[..., i, j].conj()

    E = np.linalg.eigvalsh(H)

    dk = np.sqrt(((k[1:]-k[:-1])**2).sum(axis=1))
    kdist = np.insert(np.cumsum(dk), 0, 0)

    fig, ax = plt.subplots()
    lines = ax.plot(kdist, E, color='k', lw=0.5)
    ax.set(ylabel=r"$E$ (eV)",
           xticks=[kdist[0], kdist[50], kdist[100], kdist[150], kdist[200-1]],
           xticklabels=["$\Gamma$", "X", "M", "R", "$\Gamma$"])

    plt.show()




.. image-sg:: /gallery/images/sphx_glr_wannier_001.png
   :alt: wannier
   :srcset: /gallery/images/sphx_glr_wannier_001.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    /home/docs/checkouts/readthedocs.org/user_builds/fplore/envs/latest/lib/python3.8/site-packages/fplore/files/band.py:551: UserWarning: genfromtxt: Empty input file: "<_io.StringIO object at 0x7fd85ff3e9d0>"
      TH = np.genfromtxt(StringIO(TH), dtype=np.float64, ndmin=2).reshape((-1, 5))




.. GENERATED FROM PYTHON SOURCE LINES 54-55

Plot the Hamiltonian.

.. GENERATED FROM PYTHON SOURCE LINES 55-68

.. code-block:: Python


    fig, ax = plt.subplots(constrained_layout=True, ncols=2, sharex=True, sharey=True)
    im0 = ax[0].matshow(np.real(H[0])); ax[0].set_title(r"$\operatorname{Re} \mathbf{H}(k=\Gamma)$")
    im1 = ax[1].matshow(np.imag(H[0])); ax[1].set_title(r"$\operatorname{Im} \mathbf{H}(k=\Gamma)$")


    wannames_pretty = [x.replace('up','↑').replace('dn','↓') for x in ham.wannames]
    for _im, _ax in zip([im0, im1], ax):
        fig.colorbar(_im, ax=_ax, location='bottom')
        _ax.set_xticks(np.arange(ham.nwan), labels=wannames_pretty, fontsize=6, rotation=90)
        _ax.set_yticks(np.arange(ham.nwan), labels=wannames_pretty, fontsize=6)

    plt.show()



.. image-sg:: /gallery/images/sphx_glr_wannier_002.png
   :alt: $\operatorname{Re} \mathbf{H}(k=\Gamma)$, $\operatorname{Im} \mathbf{H}(k=\Gamma)$
   :srcset: /gallery/images/sphx_glr_wannier_002.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 2.194 seconds)


.. _sphx_glr_download_gallery_wannier.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: wannier.ipynb <wannier.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: wannier.py <wannier.py>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_