## Abstract

BoltzWann is a code to evaluate thermoelectric and electronic transport properties of extended systems with a maximally-localized Wannier function basis set. The semiclassical Boltzmann transport equations for the homogeneous infinite system are solved in the constant relaxation-time approximation and band energies and band derivatives are obtained via Wannier interpolations. Thanks to the exponential localization of the Wannier functions obtained, very high accuracy in the Brillouin zone integrals can be achieved with very moderate computational costs. Moreover, the analytical expression for the band derivatives in the Wannier basis resolves any issues that may occur when evaluating derivatives near band crossings. We present here an updated version of the BoltzWann code, which is now fully integrated within Wannier90 version 2.0, with minor bug fixes and the possibility to study also two-dimensional systems. New version program summary Program title: BoltzWann Catalogue identifier: AEQX_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEQX_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 925790 No. of bytes in distributed program, including test data, etc.: 47893624 Distribution format: tar.gz Programming language: Fortran 90. Computer: Any architecture with a Fortran 90 compiler. Operating system: Linux, Windows, Solaris, AIX, Tru64 Unix, OSX. Has the code been vectorized or parallelized?: Yes. Parallelized using MPI RAM: The example requires approximately 10 MB. Classification: 7.3, 7.9. External routines: BLAS and LAPACK (available on http://www.netlib.org/); MPI libraries (optional) for parallel execution Catalogue identifier of previous version: AEQX_v1_0 Journal reference of previous version: Comput. Phys. Comm. 185 (2014) 422 Does the new version supersede the previous version?: Yes Nature of problem: Obtain electronic and thermoelectric transport properties for crystals Solution method: The Boltzmann transport equations in the constant relaxation-time approximation are used. These equations require the integration of the band velocities over all the Brillouin zone; this is done numerically on a sufficiently dense k grid. Band energies and band derivatives are obtained by interpolation using the maximally-localized Wannier functions basis obtained with a preliminary run of the Wannier90 code. Reasons for new version: Small bug fixes and new features; integration within Wannier90 version 2.0 (www.wannier.org) Summary of revisions: The most important revisions are: • Integration with the Wannier90 version 2.0 code• Bug fix in the case of system with non-cubic symmetry• Now the code also outputs files for the tensor product σ. S• The full Seebeck coefficient tensor is now output, rather than only its upper diagonal• Also two-dimensional systems are now supported via the boltz_2d_dir flag Unusual features: The maximally-localized Wannier functions interpolation scheme allows the use of analytical formulas (instead of finite-difference methods) to obtain the band derivatives. Additional comments: The distribution file for this program is over 45 Mbytes and therefore is not delivered directly when Download or Email is requested. Instead an html file giving details of how the program can be obtained is sent. Running time: The example runs (in its serial version) in less than 2 minutes.

Original language | English |
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Pages (from-to) | 2311-2312 |

Number of pages | 2 |

Journal | Computer Physics Communications |

Volume | 185 |

Issue number | 8 |

DOIs | |

State | Published - Aug 2014 |

## Keywords

- Band interpolation
- Band velocities
- Maximally-localized Wannier functions
- Thermoelectric properties
- Wannier90