[QE-users] How to obatin orbital projected band structre

[Nicola Marzari]

On 28/02/2026 06:41, Narayanan Namboodiri P via users wrote:
> Dear QE Users,
> 
> 
>                         I am using QE for my DFT calculations and i want 
> to plot atom projected band structure for my compounds. Can anyone 
> kindly help me how i can plot this.
> 
> Thanking you in advance
> 
> with regards
> Narayanan

These days you do not even need chatgpt and similars - google is enough.

nicola


"I am using QE for my DFT calculations and i want to plot atom projected 
band structure for my compounds. Can anyone kindly help me how i can 
plot this."

Plotting atom-projected band structures ("fat bands") in Quantum 
ESPRESSO (QE) involves a four-step workflow: self-consistent field (SCF) 
calculation, non-self-consistent field (NSCF) band structure 
calculation, projection of wavefunctions (
projwfc.x), and plotting.
Here is the step-by-step guide to generating and plotting atom-projected 
band structures.
Step 1: Ground State (SCF) Calculation
Run pw.x to get the converged charge density.

     Input: scf.in (standard SCF input, high-quality k-mesh)
     Command: pw.x < scf.in > scf.out

Step 2: Band Structure (NSCF) Calculation
Run pw.x to calculate eigenvalues along a high-symmetry path.

     Input: bands.in (Use calculation = 'bands', define a K_POINTS 
crystal_b path)
     Command: pw.x < bands.in > bands.out
     Note: Ensure the prefix and outdir are the same as in Step 1.

Step 3: Atomic Projection (projwfc.x)
This step projects the Kohn-Sham states onto atomic orbitals.

     Input: projwfc.in
     Key parameters:
     fortran

     &PROJWFC
       prefix = 'your_prefix', outdir = './tmp/', ngauss = 0, degauss = 
0.01, Esigma = 0.01, kresolveddos = .true.  ! Required for projected bands
       filproj = 'atom_proj'
     /

     Command: projwfc.x < projwfc.in > projwfc.out
     Output: This generates files like atomic_proj.xml and *.kpdos files 
containing the projections.

Step 4: Plotting the Projected Bands
There are two main ways to plot the results:
Method A: Using pyprocar (Recommended)
pyprocar is a Python library tailored for QE to plot fat bands easily.

     Install: pip install pyprocar
     Run: Use the following Python command to generate the plot:
     python

     import pyprocar
     pyprocar.bandsplot(dirname='.', mode='atomic', code='qe')



Method B: Using projwfc.x + Gnuplot
You can extract the projected bands from projwfc.x output.

     Extract Data: Use sumpdos.x to sum projections for specific 
atoms/orbitals. For example, to sum all orbitals of atom 1:
     bash

     sumpdos.x *\(atom1\)* > atom1_proj.dat

     Plotting: Use gnuplot or matplotlib to plot the filproj.kpdos 
files, mapping the projected weight to color or band thickness.

Summary of Tools

     projwfc.x: Projects Kohn-Sham states to atomic orbitals.
     sumpdos.x: Sums desired projections.
     pyprocar: Python tool for visualizing fat bands.
     qe_pp_bands.py: Python script, often used with projwfc.x output.

Ensure you copy the atomic_proj.xml file from the .save directory to 
your working directory before running projection scripts.


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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, SNSF
Laboratory Head, PSI Center for Scientific Computing, Theory, and Data
Contact info and websites:  https://theos-wiki.epfl.ch/en/Main/Contact