#!/usr/bin/env python
# coding: utf-8

# This notebook shows some examples of methods on a BandStructureSymmLine object (gettting band gaps, vbm, etc...) and basic plotting. Written by Geoffroy Hautier (geoffroy.hautier@uclouvain.be)

# We start by querying the MP database for a band structure object. Please note that you could get such an object from a run (VASP, ABINIT, ...) using the methods in pymatgen.io
# 

# In[1]:


from pymatgen.matproj.rest import MPRester
from pymatgen.electronic_structure.core import Spin
#This initiliazes the Rest connection to the Materials Project db. Put your own API key if needed.
a = MPRester()
#load the band structure from mp-3748, CuAlO2 from the MP db
bs = a.get_bandstructure_by_material_id("mp-3748")


# We print some information about the band structure

# In[2]:


#is the material a metal (i.e., the fermi level cross a band)
print(bs.is_metal())
#print information on the band gap
print(bs.get_band_gap())
#print the energy of the 20th band and 10th kpoint
print(bs.bands[Spin.up][20][10])
#print energy of direct band gap
print(bs.get_direct_band_gap())
#print information on the vbm
print(bs.get_vbm())


# Here, we plot the bs object. By default for an insulator we have en energy limit of cbm+4eV and vbm-4 eV

# In[3]:


get_ipython().run_line_magic('matplotlib', 'inline')
from pymatgen.electronic_structure.plotter import BSPlotter
plotter = BSPlotter(bs)
plotter.get_plot().show()


# We plot the Brillouin zone with the path which was used for the band structure

# In[4]:


plotter.plot_brillouin()


# In[ ]: