MagInt

Copyright (C) 2012-2025: Leonid V. Pourovskii, 2023-2025: Dario Fiore Mosca

This program implements the force-theorem Hubbard-I (FT-HI) approach to calculation of intersite exchange interactions in correlated insulators. The formalism is given in L. V. Pourovskii Phys. Rev. B 94, 115117 (2016). It is a post-processing program that works on top of a fully converged DFT+HI calculation, and for this purpose it is interfaced with the TRIQS software library, and the DFT code interface TRIQS/DFTTools.

MagInt has been interfaced with the following bandstructure codes: Wien2k version 13 to 15. VASP version 6.3.0 or above (WARNING The VASP interface is experimental and has undergone limited testing. If you plan to use it, please contact the authors for further information or assistance.).

MagInt works with python < 3.12.

Documentation & tutorials

To learn how to use MagInt read the manual

Installation

You can install MagInt via CMake. An example for the installation bash script is given below. You need to substitute $(TRIQS_ROOT) with another name if you do not wish to install MagInt in the TRIQS installation directory.

``` rm -rf MagInt.build

Set this variable to your desired install directory

INSTALLPREFIX=$(TRIQSROOT)

Set the number of cores for the compilation

NCORES=4

Use cmake to configure the maginteract build process

mkdir -p MagInt.build && cd MagInt.build

cmake ../MagInt.src -DCMAKEINSTALLPREFIX=$INSTALL_PREFIX

Build, test and install triqs

make -j $NCORES make install make test cd ../ ```

Usage

In the following the main commands are outlined. For each step a 'maginteract.ini' file is required. Have a look at the Documentation and Tutorials for more information

1. Calculation Density of States

python /path/to/MagInt/main.py dos

1. In the cases, when the chemical potential mu in the calcualated DOS (step 1) is not strictly within the gap but is pinned slightly below/above it, the mu should be shifted by executing

python /path/to/MagInt/main.py shift_mu

1. Calcualting the Pseudo-Spin basis

For this step a problem-specific script is required, see the documentation for details and some examples in ./Examples

1. Calculation of Intersite-exchange-interactions

python /path/to/MagInt/main.py magint

Please make sure that you have a valid TRIQS and TRIQS/DFTTools installation matching the required versions for MagInt.

Within the current version of MagInt we provide FORTRAN Hubbard-I solver.

authors: L. V. Pourovskii and D. Fiore Mosca

LICENCE

This application is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version (see http://www.gnu.org/licenses/).

It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.