P-TRANS: A Monte Carlo ray-tracing software to simulate phonon transport in arbitrary nanostructures

P-TRANS is a software to simulate phonon transport in arbitrary nanostructures based on the Boltzmann transport theory. The core part of the software is a Monte Carlo ray-tracing solver that uses the stochastic method to sample phonon transport in various nanostructures. The solver is written in FORTRAN with well-organized modules and utilizing the OpenMP and MPI parallelization to achieve high performance. The software can handle a typical calculation of nanostructures with a feature size of ∼1000 nm on a normal PC within seconds, which is useful when exploring the wide variety of structures, for instance for structural optimization or high-throughput screening in material informatics. The software takes the bulk phonon properties obtained from the first-principles anharmonic lattice dynamics calculations as inputs. The database of bulk phonon properties is available on the software webpage, which currently contains more than 60 materials and will increase in the future. We also provide a graphical user interface to design the nanostructures and to run the simulation for non-expert users. In this paper, we introduce the theoretical background, the technical details and implementation, and the applications of the software.

P-TRANS是一款基于玻尔兹曼输运理论（Boltzmann transport theory），用于模拟任意纳米结构内声子（phonon）输运过程的软件。该软件的核心模块为蒙特卡洛射线追踪求解器，其通过随机采样方法对各类纳米结构中的声子输运过程进行模拟。此求解器采用FORTRAN语言编写，模块架构清晰合理，并通过OpenMP与MPI并行技术实现高性能计算。该软件可在普通个人电脑上，于数秒内完成特征尺寸约1000纳米的典型纳米结构计算，在探索多样化结构场景中具备极高应用价值，例如可用于材料信息学领域的结构优化与高通量筛选。软件的输入数据源为通过第一性原理非谐晶格动力学计算得到的块体声子特性参数。块体声子特性数据库可在该软件官方网页获取，目前已收录60余种材料，后续还将持续扩充更新。我们还为非专业用户提供了图形用户界面，用于纳米结构的设计与模拟运行。本文中，我们将介绍该软件的理论背景、技术细节、实现方案及其应用场景。