ShengBTE is a software package for solving the Boltzmann Transport Equation for phonons. Its main purpose is to compute the lattice contribution to the thermal conductivity of bulk crystalline solids, but nanowires can also be treated under a hypothesis of diffusive boundary conditions. In addition to the thermal conductivity itself, ShengBTE computes and outputs plenty of additional information about the system under study. See the Features page for a more complete description. Our method is fully parameter-free, and within its limits of applicability it can yield excellent agreement with experiment. In contrast with parametric methods, it can also be used to predict the lattice thermal conductivity of uncharacterized or even as-yet-unsynthesized materials.

As inputs, ShengBTE needs sets of 2nd- and 3rd-order interatomic force constants, and possibly also values of the dielectric parameters of the solid. This set of variables is typically computed ab initio using a DFT package such as VASP or Quantum Espresso. In some occasions these programs can compute 2nd-order constants directly; in others, auxiliary software such as Phonopy needs to be used to facilitate the process. We have developed our own software, thirdorder.py, to fulfill a similar role in the third-order calculations. This site is also the home of thirdorder.py.

Both ShengBTE and thirdorder.py are free sofware, licensed under the GNU General Public License version 3 or later. We encourage contributions to this project. If you are interested, please see the Development page for details. If you just want to use them, proceed to the Downloads section. Complete usage documentation in included with both packages, but you may find it more convenient to access those files from the Documentation page.

If you use ShengBTE and/or thirdorder.py and publish your results, please support our work by citing us.