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effmass
What effmass is
effmass is a free Python package for analyzing semiconductor electronic bandstructures. It calculates curvature, transport, and optical effective masses, with optical calculations using a Kane dispersion assumption. Kane parameters help assess non-parabolic behavior over a selected energy range. The package can find valence-band maxima and conduction-band minima, including extrema within a specified range, and can plot selected bandstructure sections with quadratic, Kane, or higher-order approximations. It also estimates a quasi-Fermi level from density-of-states data without thermal smearing; this option supports VASP and requires DOSCAR output. Documentation lists VASP, FHI-Aims, Castep, and ASE support. The command-line interface covers basic parabolic calculations, while the Python API exposes non-parabolic definitions. Installation is documented through pip, conda, or GitHub. The project is MIT licensed and aimed at theoretical solid-state physicists and chemists familiar with Python.
Who it suits
effmass suits theoretical solid-state physicists and chemists with basic Python familiarity. It is useful for researchers working with the listed electronic-structure codes.
What it does well
- Calculates several effective-mass types
- Assesses non-parabolicity with Kane parameters
- Locates band extrema
- Plots dispersion approximations
- Available free on Linux, macOS, and Windows
What to know first
- Quasi-Fermi estimates require VASP DOSCAR
- Command line handles only basic parabolic calculations
- GitHub version is described as unstable
- Requires Python familiarity
Verdict
effmass provides focused semiconductor bandstructure calculations through both command line and Python interfaces. Its broader non-parabolic analysis and quasi-Fermi estimate are available through the package’s documented workflows and dependencies.
Facts from effmass's own pages
- Band extrema
- It can locate valence band maxima and conduction band minima, including extrema within an energy range. · effmass.readthedocs.io, 5 Oct 2026
- Bandstructure analysis
- It locates valence band maxima and conduction band minima, including extrema within a specified energy range. · effmass.readthedocs.io, 12 Oct 2026
- Command line and API
- The command line interface provides basic parabolic effective mass calculations, while the Python API provides access to non-parabolic definitions. · effmass.readthedocs.io, 5 Oct 2026
- Distribution
- The package can be installed with pip or from its GitHub repository; the repository describes the GitHub version as unstable. · github.com, 12 Oct 2026
- Effective mass calculations
- It calculates curvature, transport and optical effective masses, including optical mass under a Kane dispersion assumption. · effmass.readthedocs.io, 5 Oct 2026
- Effective masses
- It calculates curvature, transport, and optical effective masses, with optical mass calculated assuming a Kane dispersion. · effmass.readthedocs.io, 12 Oct 2026
- Free plan
- Yes · effmass.readthedocs.io, 23 Sept 2026
- Installation
- The maker's repository documents installation with pip or in a conda environment and also describes installing from GitHub. · github.com, 5 Oct 2026
- Integration dependency
- The package uses vasppy to parse VASP output and ASE to parse Castep output. · effmass.readthedocs.io, 5 Oct 2026
- Intended users
- The package is aimed at theoretical solid-state physicists and chemists with basic familiarity with Python. · effmass.readthedocs.io, 12 Oct 2026
- Interface
- The command-line interface provides basic parabolic effective-mass calculations, while the Python API provides access to non-parabolic definitions. · effmass.readthedocs.io, 12 Oct 2026
- License
- PyPI lists the package under the MIT License. · pypi.org, 12 Oct 2026
- Maker and authorship
- The documentation names Lucy Whalley as the author and identifies Northumbria University in the contact email address. · effmass.readthedocs.io, 5 Oct 2026
- Non-parabolicity
- It calculates Kane dispersion parameters to assess non-parabolicity over an energy range. · effmass.readthedocs.io, 12 Oct 2026
- Plots
- It can plot selected bandstructure segments and quadratic, Kane or higher-order dispersion approximations. · effmass.readthedocs.io, 5 Oct 2026
- Purpose
- effmass is a Python package for calculating effective mass from the electronic bandstructure of a semiconductor. · effmass.readthedocs.io, 12 Oct 2026
- Quasi-Fermi estimate
- It estimates the quasi-Fermi level from density-of-states data without thermal smearing; this feature supports VASP and requires DOSCAR. · effmass.readthedocs.io, 5 Oct 2026
- 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. · effmass.readthedocs.io, 12 Oct 2026
- Research citation
- The documentation asks users to cite Lucy Whalley's 2018 Journal of Open Source Software paper when using the code in research. · effmass.readthedocs.io, 12 Oct 2026
- Support
- The project asks users to use its GitHub issue tracker for questions, feature requests, and bug reports. · github.com, 12 Oct 2026
- Supported codes
- The documentation lists VASP, FHI-Aims, Castep, and ASE as supported codes. · effmass.readthedocs.io, 12 Oct 2026
- Visualization
- It plots selected bandstructure segments and Kane, quadratic, or higher-order approximations to the dispersion. · effmass.readthedocs.io, 12 Oct 2026
Where effmass stands on Freedom251
- Physics Simulation Software#63 of 89