C-BerryTrans: A C++ code for first-principles calculation of Berry-curvature-driven anomalous Hall and Nernst conductivities

Abstract

We present \textit{C-BerryTrans}, a C++ code for \textit{ab-initio} calculations of Berry-curvature-driven AHC \textit{i.e.}, $\sigma_{\mu \nu}^{AHC}$ and ANC \textit{i.e.}, $\alpha_{\mu \nu}^{ANC}$. The code extracts eigenvalues and momentum-matrix from WIEN2k calculations and evaluates the Berry curvature using a Kubo-like formalism. It parallelizes $\boldsymbol\Omega$ evaluation over \textbf{\textit{k}}-points and stores band-resolved curvature data in binary format. This design enables rapid post-processing of AHC and ANC over a wide range of temperature ($T$) and chemical potential ($\omega$) values in a single run. The code is benchmarked on ferromagnetic materials- Fe, Fe$_3$Ge, Pd, Fe$_3$Al, and Co$_2$FeAl. For Fe, the $\sigma_{xy}^{AHC}$ is obtained to be $\sim$775 ($\sim$744) $S/cm$ at 0 (300) $K$. For Fe$_3$Ge, the value of $\sigma_{xy}^{AHC}$ is 311 $S/cm$ at 300 $K$. Nextly, for Co$_2$FeAl, the computed value of $\sigma_{xy}^{AHC}$ at 2 $K$ is $\sim$56 $S/cm$. Moving further, magnitude of $\alpha_{xy}^{ANC}$ for Pd is found as $\sim$0.97 $AK^{-1}m^{-1}$ at 300 K. For Fe$_3$Al, the maximum magnitude of $\alpha_{xy}^{ANC}$ for $T\leq$500 $K$ is computed as $\sim$2.83 $AK^{-1}m^{-1}$. Lastly, for Co$_2$FeAl, the value of $\alpha_{xy}^{ANC}$ is found to be $\sim$0.10 $AK^{-1}m^{-1}$ at 300 $K$. These results show good agreement with the reported data. With its accuracy and user-friendly workflow, \textit{C-BerryTrans} provides a powerful tool for exploring $\boldsymbol\Omega$-driven transport and is well suited for high-throughput materials discovery. The code also enables the evaluation of $\boldsymbol\Omega$-derived AHC/ANC contributions along user-defined \textbf{\textit{k}}-point paths. Additionally, the code is equipped with a visualization module that allows analysis of \textbf{\textit{k}}-point contributions to AHC or ANC in any material.