How to calculate the Total and Partial DOS of antifferromagnetic Nickel Oxide NiO

POSCAR

AFM  NiO
 4.17
 1.0 0.5 0.5
 0.5 1.0 0.5
 0.5 0.5 1.0
 2 2
Cartesian
 0.0 0.0 0.0
 1.0 1.0 1.0
 0.5 0.5 0.5
 1.5 1.5 1.5

     

INCAR

SYSTEM   = NiO

ISTART   = 0

ISPIN    = 2
MAGMOM   = 2.0 -2.0 2*0 

ENMAX    = 250.0
EDIFF    = 1E-3

ISMEAR   = -5

AMIX     = 0.2
BMIX     = 0.00001
AMIX_MAG = 0.8
BMIX_MAG = 0.00001

LORBIT   = 11

 

KPOINTS

k-points
 0
gamma
 4  4  4 
 0  0  0

 

POTCAR

Download the pseudopotential file from this link NiO.tgz

SCF and DOS calculations

/Ni_dos> vasp_std

 

 Plotting DOS

To get a nice plotting we will another script called  plotDOS.py from the  package:       MatSciScripts

To use the script we need to install the Pymatgen library. To install this library check the following link:

How to download and install the Pymatgen library

 

Now we need to create a tools directory inside the root directory

> cd $VASPROOT
/vasp.5.4.1> mkdir tools

and copy the script plotDOS.py inside this created directory

> cp path/MatSciScripts/plotDOS.py $VASPROOT/tools/plotDOS.py

 

 At the end we need to add the path of tools directory to the path of vasp code as follows:

VASPROOT=/home/algerien1970/abinitio/vasp.5.4.1
export PATH=$PATH:$VASPROOT
export VASPBIN=$VASPROOT/bin 
export VASPTOOLS=$VASPROOT/tools

Total DOS

This is the total contribuition from all the atoms and orbitals in the system.

Run:

plotDOS.py total -show

The -show flag displays the plot on screen. Otherwise it would just save the figure as a .png file. As you can see since there are states at the Fermi level this is classified as a metal. The total DOS is rather boring so let’s move on to plotting partial DOS where we can see the different contributions of atoms and orbitals to the DOS.

 

Partial DOS

Atom Projected DOS

This plots the contribution to the DOS from each atom.

Run:

plotDOS.py atomic -show

 

 

To see both the total and the atomic contributions on the same plot you may add the -total flag to the above command.

 Since we have one atom Ni the total DOS is the same atomic DOS.

Orbital projected DOS

 

Next, let’s see how each orbital from the atoms contribute to the DOS. This enables us to observe how much each s, p, d or f orbital of a certain atom is present in the DOS. E.g. - Ni atom contribution

Run:

plotDOS.py orbital -atom Ni -show

 

The -total flag works here as well if one wishes to see the total contribution for the orbital on the same plot.

 

d-orbital projected DOS

In certain materials like strongly correlated systems where d orbitals play a vital role in conductivity and other properties, it is important to study the decomposed d-orbital projected DOS. i.e. the individual effects of the e\(_g\) and t\(_{2g}\) orbitals when the degeneracy of the d orbital is broken. Let’s consider the same example as above and investigate how the Ni d-orbitals behave.

Run:

plotDOS.py orbital_d -atom Ni -show