turboMagnon - A code for the simulation of spin-wave spectra using Liouville-Lanczos approach to time-dependent density-functional perturbation theory

We introduce turboMagnon, an implementation of the Liouville-Lanczos approach to linearized time-dependent density-functional theory, designed to simulate spin-wave spectra in solid-state materials. The code is based on the noncollinear spin-polarized framework and the self-consistent inclusion of spin-orbit coupling that allow to model complex magnetic excitations. The spin susceptibility matrix is computed using the Lanczos recursion algorithm that is implemented in two flavors - the non-Hermitian and the pseudo-Hermitian one. turboMagnon is open-source software distributed under the terms of the GPL as a component of QE. As with other components, turboMagnon is optimized to run on massively parallel architectures using native mathematical libraries (LAPACK and FFTW) and a hierarchy of custom parallelization layers built on top of MPI. The effectiveness of the code is showcased by computing magnon dispersions for the CrI₃ monolayer, and the importance of the spin-orbit coupling is discussed.

本文介绍了turboMagnon：一种面向线性化含时密度泛函理论（linearized time-dependent density-functional theory）的Liouville-Lanczos方法实现，旨在模拟固态材料中的自旋波谱。该程序基于非共线自旋极化框架与自旋轨道耦合（spin-orbit coupling）的自洽纳入方案，可用于建模复杂磁激发过程。自旋磁化率矩阵（spin susceptibility matrix）的计算采用Lanczos递推算法，该算法提供两种实现形式：非厄米形式与伪厄米形式。turboMagnon是基于GPL协议开源的软件，作为QE的组件进行分发。与其他组件一致，turboMagnon针对大规模并行架构进行了优化，可依托原生数学库（LAPACK与FFTW）以及基于MPI构建的多层自定义并行化层实现运行。本文通过计算三碘化铬（CrI₃）单层的磁子色散曲线展示了该程序的有效性，并讨论了自旋轨道耦合的重要作用。