C-BerryTrans : A C++ code for first-principles calculation of Berry-curvature-driven anomalous Hall and Nernst conductivities
Description
We present C-BerryTrans, a C++ code designed for first-principles calculations of Berry-curvature-driven transverse transport properties, namely the anomalous Hall conductivity (AHC) i.e., σ_{μν}^{AHC} and anomalous Nernst conductivity (ANC) i.e., α_{μν}^{ANC}. The code directly extracts eigenvalues and momentum-matrix elements from WIEN2k calculations and evaluates the Berry curvature (Ω) using a Kubo-like formalism, thereby avoiding the interpolation errors inherent in Wannier-based approaches. To ensure computational efficiency, C-BerryTrans parallelizes Ω evaluation over k-points using OpenMP and stores band-resolved curvature data in binary format, significantly reducing memory usage. This design enables rapid post-processing of AHC and ANC over a wide range of temperature (T) and chemical potential (ω) values in a single run. The code has been benchmarked on well-studied ferromagnetic materials- Fe, Fe3Ge, Pd, Fe3Al, and Co2FeAl. For Fe, the σ_{xy}^{AHC} is obtained to be ∼ 775 ( ∼ 744) S/cm at 0 (300) K. In case of Fe3Ge, the calculated value of σ_{xy}^{AHC} is found to be 311 S/cm at 300 K. Nextly, for Co2FeAl, the magnitude of computed value of σ_{xy}^{AHC} at 2 K is found to be ∼ 56 S/cm. Moving further, the room temperature magnitude of α_{xy}^{ANC} for Pd is obtained to be ∼ 0.97 AK^{-1}m^{-1}. In case of Fe3Al, the maximum magnitude of α_{xy}^{ANC} for T ≤ 500 K is computed as ∼ 2.83 AK^{-1}m^{-1}. Lastly, for Co2FeAl, the value of α_{xy}^{ANC} is obtained to be ∼ 0.10 AK^{-1}m^{-1} at 300 K. These results show excellent agreement with previously reported data. With its accuracy, scalability, and user-friendly workflow, C-BerryTrans provides a powerful tool for exploring Ω-driven transport phenomena and is well suited for high-throughput materials discovery. The code further enables the evaluation of Ω-derived AHC/ANC contributions along user-defined high-symmetry k-point paths. This provides valuable microscopic insight into how specific band-structure features contribute to Ω-driven AHC/ANC. Additionally, the code is equipped with a visualization module that allows analysis of k-point contributions to AHC or ANC in any material. This further enhances its capability for exploring topological materials.