News

Feature release

Bug fixes

• Show more instructive error message if a material argument is not followed by a valid material id
• Recalculate or invalidate derivatives if band alignment has changed in kdotpy merge
• Fix exception with checking script directories on different drives in Windows
• Fix exception in kdotpy batch when no variable substitutions are given

Implementation changes

• Improve potential file imports
• Allow y coordinates of spatial lattice to be chosen at integer multiples or at half integer multiples of the resolution
• Save model options into XML output
• Optimize plot handling for 2D band plots

New features

• Apply potentials of the form V(y, z) in kdotpy 1d; accept csv files with grid-type or mesh-type data, and use interpolation if needed
• Optical transitions for bulk Landau level calculations (kdotpy bulk-ll)
• Add filter for material files
• Add helper functions for serialization (for future use)
• Local density of states in multiple dimensions (kdotpy 2d)
• Density as function of y and z (kdotpy 1d)
• Binary output files (Numpy npz format) for local density of states in two dimensions and for density as function of y, z, and energy
• Band alignment in kdotpy 1d (manual only)
• Cache eigenstates with binary files in kdotpy 1d

Miscellaneous

• Add license metadata in pyproject.toml following PEP 639

Unfortunately, the kdotpy website and the Gitlab server encountered an unexpected downtime earlier today, caused by a power outage. At this time, the services are back online. Apologies for the inconvenience.

At the upcoming DPG Spring Meeting (Frühjahrstagung) in Regensburg, we will present several exciting talks about kdotpy and its results:

• Wouter Beugeling et al.
  kdotpy: A Python application for k·p band structure simulations of zincblende semiconductors
  HL12.1, Monday 16:45, room H15

• Maximilian Hofer et al.
  Surface state dominated transport in HgTe topological insulator devices
  HL12.5, Monday 17:45, room H15

• Leonid Bovkun et al.
  Topological Phase Diagram of Mercury Cadmium Telluride Quantum Wells
  HL13.6, Monday 18:00, room H17

  [Read More]

Bugfix release

Bug fixes

• Provide fallback for kdotpy help in case the less command is not available (primarily a Windows issue)
• Fix incorrect quantity being shown in dsigmah-de plot (for kdotpy ll with hall)
• Show more instructive error messages when estimation of CNP fails, for example if the split argument is omitted
• Fix inconsistency between pdf and csv output of wave functions for LL calculations in full LL mode

Feature release

Bug fixes

• Make kdotpy compatible with Numpy 2
• Fix pending deprecations for future Scipy and Python versions

Implementation changes

• Replace hard-coded strain ratio C12/C11 by value from material parameters
• Simplify the implementation for iterators in kdotpy batch
• Make sign of carrier/charge density more consistent internally

New features

• Add elasticity parameters as material parameters
• Add grouped iterators in kdotpy batch, which are iterated through simultaneously
• Enable input of charge density per layer, for simulations of modulation doping

We welcome Julian Kuther as a new contributor. Thanks to Julian for his work on the elasticity parameters!

Our article about kdotpy release 1.0.0 has been offically published by SciPost Physics Codebases! 🎉

Please view the article at https://scipost.org/SciPostPhysCodeb.47.
[DOI: 10.21468/SciPostPhysCodeb.47]

The codebase published with the article can be found at the journal repository. Note that this journal repository will be updated less frequently than our live Gitlab repository.

You are encouraged to credit us by citing the article and/or the codebase, indicating the relevant release/version number.

W. Beugeling, F. Bayer, C. Berger, J. Böttcher, L. Bovkun, C. Fuchs, M. Hofer, S. Shamim, M. Siebert, L.-X. Wang, E. M. Hankiewicz, T. Kießling, H. Buhmann, and L. W. Molenkamp, “kdotpy: k·p theory on a lattice for simulating semiconductor band structures”, SciPost Phys. Codebases 47 (2025).

[Read More]

Bugfix release

Bug fixes

• Fix an incompatibility with matplotlib version 3.10.0, leading to an exception for some DOS plots

Miscellaneous

• Update citation information following publication of our article and codebase in SciPost Physics Codebases

Bugfix release

Bug fixes

• Fix incorrect prefix handling for vector grid and vector transformation
• No longer create transformable Hamiltonian if stripangle is used
• Fix false negatives for thickness commensurability test
• Let kdotpy test use python -m kdotpy, so that it can be run if kdotpy is not in PATH
• Fix incorrect display of unparsed arguments
• Improve error messages for invalid command line arguments (e.g., vector grid, material, and layer stack arguments)
• Fix infinite loop in contour plot if minimum and maximum value are equal
• Fix errors in observable strings
• Fix exception if there are no extrema
• No longer ignore table_extrema_precision configuration value

Implementation changes

• Slight difference in handling of vector grid arguments (k and/or b), in order to improve error messages for invalid input
• Disallow underscore as separator in matparam argument in order to prevent parsing errors

Acknowledgement: We thank the reviewers of our SciPost submission for bringing some of these issues to our attention. See the SciPost submissions page for more information.

Our first major release 🎉

(Changes since v0.95)

Bug fixes

• Optimize eigenvalue stitching
• Fix incorrect union and intersection operations on (energy) intervals
• Workaround for random matplotlib bug involving contour labels
• Fix problem with inadvertently changed property obsids in DiagDataPoint
• Use correct length scaling when calculating derivatives of band structure parameters exactly (dz = 0)
• Fix problems with colours in legends
• Fix problem with ETransform with plotstyle normal
• Catch rare case for kdotpy 1d where list of wave function locations is empty
• Fix bug in 19-point extremum solver (3D)
• Fix error in finding CNP when band characters are unavailable
• Raise warning about using CuPy solver with kdotpy 2d
• Fix empty unit string in legend for dual observable
• Disable BHZ plot if figure is absent
• Fix problem with extrema for spherical coordinates
• Fix handling of radians as angular units for extrema
• Do not reject valid input in imported colormaps
• Fix inconsistent composition of columns in transitions table
• Fix error in adiabatic band alignment if zero energy is undefined
• Fix units in transitions output

Implementation changes

• Packaging: turn kdotpy into a package that can be installed with pip
• Update version requirements for Python, NumPy, SciPy, and Matplotlib; update code accordingly
• Replace shell scripts by Python implementations (increase OS compatibility)
• Clean up unused code; delete unused variables and function arguments
• Restructure program, simplify internal dependencies (imports)
• Improved plot customization: Use Matplotlib style files instead of matplotlibrc; use rcparams more consistently
• Improved colormap handling
• Streamline csv output: Separate construction and writing of data
• Improved, but stricter checking on CNP
• Optimize band alignment
• Remove restrictions on broadening; enable B-dependent broadening for self-consistent Hartree in LL mode
• Change some default configuration settings
• Remove deprecated command-line arguments

New features

• Material parameter files: Material parameters are no longer hardcoded, but provided by the user as separate files in the configuration directory (more details in Wiki)
• Selfconsistent Hartree with full diagonalization (dispersion and LL mode)
• Support for JAX eigh diagsolver
• Band alignment succeeds without CNP being defined
• Doxygen generated developer documentation
• Infrastructure for configuration key deprecation

The preprint that goes together with release 1.0.0 is available now!

W. Beugeling, F. Bayer, C. Berger, J. Böttcher, L. Bovkun, C. Fuchs, M. Hofer, S. Shamim, M. Siebert, L.-X. Wang, E. M. Hankiewicz, T. Kießling, H. Buhmann, and L. W. Molenkamp, kdotpy: k·p theory on a lattice for simulating semiconductor band structures, arXiv:2407.12651 (2024)