effmass

Spec sheet

Purpose

effmass is a Python package for calculating effective mass from the electronic bandstructure of a semiconductor.Read 12 Oct 2026 · effmass.readthedocs.io

Intended users

The package is aimed at theoretical solid-state physicists and chemists with basic familiarity with Python.Read 12 Oct 2026 · effmass.readthedocs.io

Free plan

YesRead 23 Sep 2026 · effmass.readthedocs.io

Support

The project asks users to use its GitHub issue tracker for questions, feature requests, and bug reports.Read 12 Oct 2026 · github.com

License

PyPI lists the package under the MIT License.Read 12 Oct 2026 · pypi.org

Band extrema

It can locate valence band maxima and conduction band minima, including extrema within an energy range.Read 5 Oct 2026 · effmass.readthedocs.io

Bandstructure analysis

It locates valence band maxima and conduction band minima, including extrema within a specified energy range.Read 12 Oct 2026 · effmass.readthedocs.io

Command line and API

The command line interface provides basic parabolic effective mass calculations, while the Python API provides access to non-parabolic definitions.Read 5 Oct 2026 · effmass.readthedocs.io

Distribution

The package can be installed with pip or from its GitHub repository; the repository describes the GitHub version as unstable.Read 12 Oct 2026 · github.com

Effective mass calculations

It calculates curvature, transport and optical effective masses, including optical mass under a Kane dispersion assumption.Read 5 Oct 2026 · effmass.readthedocs.io

Effective masses

It calculates curvature, transport, and optical effective masses, with optical mass calculated assuming a Kane dispersion.Read 12 Oct 2026 · effmass.readthedocs.io

Installation

The maker's repository documents installation with pip or in a conda environment and also describes installing from GitHub.Read 5 Oct 2026 · github.com

Integration dependency

The package uses vasppy to parse VASP output and ASE to parse Castep output.Read 5 Oct 2026 · effmass.readthedocs.io

Interface

The command-line interface provides basic parabolic effective-mass calculations, while the Python API provides access to non-parabolic definitions.Read 12 Oct 2026 · effmass.readthedocs.io

Maker and authorship

The documentation names Lucy Whalley as the author and identifies Northumbria University in the contact email address.Read 5 Oct 2026 · effmass.readthedocs.io

Non-parabolicity

It calculates Kane dispersion parameters to assess non-parabolicity over an energy range.Read 12 Oct 2026 · effmass.readthedocs.io

Plots

It can plot selected bandstructure segments and quadratic, Kane or higher-order dispersion approximations.Read 5 Oct 2026 · effmass.readthedocs.io

Quasi-Fermi estimate

It estimates the quasi-Fermi level from density-of-states data without thermal smearing; this feature supports VASP and requires DOSCAR.Read 5 Oct 2026 · effmass.readthedocs.io

Quasi-Fermi level

It estimates the quasi-Fermi level for a given carrier concentration from density-of-states data without thermal smearing; this feature requires VASP and its DOSCAR output file.Read 12 Oct 2026 · effmass.readthedocs.io

Research citation

The documentation asks users to cite Lucy Whalley's 2018 Journal of Open Source Software paper when using the code in research.Read 12 Oct 2026 · effmass.readthedocs.io

Supported codes

The documentation lists VASP, FHI-Aims, Castep, and ASE as supported codes.Read 12 Oct 2026 · effmass.readthedocs.io

Visualization

It plots selected bandstructure segments and Kane, quadratic, or higher-order approximations to the dispersion.Read 12 Oct 2026 · effmass.readthedocs.io

Where Specifiction places it

• Physics Simulation Software#78 of 897.0