v1.3.1 hotfix

Changelog:

• Added missing include on Exciton.hpp

v1.3.1

Changelog:

• Fixed bug where the BSE matrix would be initialized to zero due to an integer overflow for big systems (dim BSE > 40k).
• Removed unused variable HK which required the same memory as the BSE.
• kineticEnergy method from Results now computes the band energy for each electron-hole pair before computing the total band (or kinetic) energy of the exciton.
• Critical integer variables have been changed to uint64 so bigger systems should be accessible now with the current implementation.

v1.3.0

Changelog:

• Added 'regularization' keyword in exciton configuration files to allow modification of the renormalization length used in the real-space method. This value is set by default to the primitive cell lattice parameter.
• Added 'potential' and 'exchange.potential' keywords in exciton configuration files to allow selection of the potential used for the direct term and the exchange term (if present). These parameters only apply to real-space calculations; reciprocal space ones can still only use the Keldysh potential.
• Coulomb potential can now be used for real-space calculations.
• Enabled OMP parallelization of the calculation of the real-space electronic density of the excitons.
• Enabled OMP parallelization (of a part) of the conductivity calculation.
• Fixed a bug in SystemConfiguration where it would not compute correctly the number of chemical species if they were not ordered in the motif list.
• Automatic detection of triangular matrices in configuration files: Now the hamiltonian and overlap matrices can be given in triangular form or in complete form in the modelfiles or HDF5 files , and will automatically be detected when passed to build a SystemTB or ExcitonTB object to build properly H(k) and S(k).
• Refactorization of the class hierarchy in the code: The previous Exciton and System classes are now called SystemTB and ExcitonTB, and they implement all the details relative to how to compute excitons in the tight-binding approximation. The new System and Exciton classes are abstract template classes, used to enforce a common interface in the different child classes (i.e. ExcitonTB and SystemTB).
• Access to SystemTB within ExcitonTB is now done via pointers (composition) instead of direct inheritance from SystemTB.
• Added example plotting scripts for easy visualization of the outputs of the code.
• Removed unused method and declarations from several classes (Lattice and ExcitonTB).

v.1.2.1

Changelog:

• Added format flag to the Xatu binary, -f --format to specify the format of the system input file.
• Added support for system input files in HDF5 format.
• Modified Makefile to enable conditional compilation depending on whether the HDF5 format will be used or not.
• Added conditional flag DEBUG to Makefile to enable easier usage of the debugger with the library.

v1.2.0

Changelog:

• Optimization of the calculation of the interaction matrix elements, resulting in notably faster calculations for systems with large unit cells.
• Parallelization of exciton velocity method.
• Removed logging from CrystalDFTConfiguration
• Added hashing utility
• Added Catch2 library header to run tests
• Added multiple regression tests to ensure the reproducibility of the results shown in the Xatu paper
• Refactored Kubo module with the addition of a routine to compute the oscillator strength
• Exciton oscillator strengths now also written in absorption calculations
• Method to add Zeeman Hamiltonian to the single-particle Hamiltonian in System
• Fixed calculation of the spin of the exciton (spinX method)
• Removed empty file created by the main executable when the user wanted to compute the absorption (.abs file)
• Added method to compute the matrix elements of the single-particle velocity.
• Now totalCells is properly updated when running reduced Brillouin zone calculations.

v1.1.1

Changelog:

• Fix exciton velocity calculation
• The velocity method in the Result class now computes always both the center-of-mass velocity of the exciton and the relative velocity of its components.

v1.1

Changelog:

• Parallelized calculation of the lattice Fourier transform when using the real space calculation method.
• Removed progress bar of lattice Fourier transform as it does not work properly in parallel environments.
• Added setter for the exchange interaction.
• Added routine to calculate the velocity of an exciton (available from the Results class).
• Added support for CRYSTAL open-shell calculations.
• Added example of reciprocal space calculation to the example files.

v1.0.1 hotfix

• Fixed integer overflow when building BSE matrix for high system sizes (BSE dim > 25000)

First release

First release of the Xatu code