sim-trhepd-rheed – Open-source simulator of total-reflection high-energy positron diffraction (TRHEPD) and reflection high-energy electron diffraction (RHEED)

The present paper reports sim-trhepd-rheed (STR), an open-source simulator of total-reflection high-energy positron diffraction (TRHEPD) and reflection high-energy electron diffraction (RHEED) experiments which are used for atom-scale surface structure determination of a material. Diffraction data obtained by these experiments are analyzed by comparison with numerical simulations. The STR simulator is used for the analysis of experimental diffraction data by simulating the rocking curve from a given trial surface structure by solving the partial differential equation of the dynamical quantum diffraction theory for positron or electron wavefunctions. Using the obtained surface structure, electronic structure, and other physical quantities can be evaluated through first-principles calculations. For this purpose, a utility software was also developed in order to realize a first principles calculation with the Quantum ESPRESSO suite.

本论文报道了sim-trhepd-rheed（简称STR）开源模拟器，该模拟器用于模拟全反射高能正电子衍射（total-reflection high-energy positron diffraction, TRHEPD）与反射高能电子衍射（reflection high-energy electron diffraction, RHEED）两类实验，此类实验常用于实现材料的原子级表面结构测定。通过此类实验获取的衍射数据，需通过与数值模拟结果比对完成分析。STR模拟器可通过求解针对正电子或电子波函数的动力学量子衍射理论偏微分方程，基于给定的试算表面结构模拟摇摆曲线，以此完成实验衍射数据的分析工作。基于获取的表面结构，可通过第一性原理计算评估材料的电子结构及其他物理量。为此，研究团队还开发了一款配套工具软件，以实现基于Quantum ESPRESSO套件的第一性原理计算。