Tutorial: Plotting a Band Structure

Tutorial: Plotting a Band Structure#

This tutorial will guide you through the process of parsing eigenvalue data from a DFT calculation and using dftio to plot the electronic band structure.

1. Prerequisites#

Before you begin, make sure you have:

  • Installed dftio with its dependencies.

  • A completed DFT calculation that includes band structure data. For this tutorial, we will use the VASP example included in the dftio repository at example/vasp/GaAs/.

2. Parse the Eigenvalue Data#

First, we need to parse the eigenvalue data from the VASP output files. We will use the dftio parse command, specifying the vasp mode and the --eigenvalue flag.

dftio parse \
  --mode vasp \
  --root example/vasp/GaAs \
  --outroot ./parsed_bands

This command will create a directory named parsed_bands containing a file 0.dat, which holds the parsed eigenvalues and k-points.

3. Plot the Band Structure#

Now that we have the parsed data, we can use the dftio band command to generate a plot.

dftio band -r ./parsed_bands

This command will:

  1. Load the data from the ./parsed_bands directory.

  2. Generate a plot of the band structure.

  3. Save the plot as a file named band.png in the current directory.

You can customize the plot using various options. For example, to plot only a specific range of bands, you can use the --min and --max flags:

# Plot bands from index 10 to 20
dftio band -r ./parsed_bands --min 10 --max 20

For a full list of options, run dftio band --help.

Conclusion#

This tutorial demonstrated how to use dftio’s command-line tools to easily parse and visualize electronic band structures from DFT calculations. This two-step process (parse and plot) provides a quick and efficient way to analyze your results without writing any code.

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