Data-analysis software framework 2DMAT and its application to experimental measurements for two-dimensional material structures

Abstract

An open-source data-analysis framework 2DMAT has been developed for experimental measurements of two-dimensional material structures. 2DMAT offers five analysis methods: (i) Nelder-Mead optimization, (ii) grid search, (iii) Bayesian optimization, (iv) replica exchange Monte Carlo method, and (v) population-annealing Monte Carlo method. Methods (ii) through (v) are implemented by parallel computation, which is efficient not only for personal computers but also for supercomputers. The current version of 2DMAT is applicable to total-reflection high-energy positron diffraction (TRHEPD), surface X-ray diffraction (SXRD), and low-energy electron diffraction (LEED) experiments by installing corresponding forward problem solvers that generate diffraction intensity data from a given dataset of the atomic positions. The analysis methods are general and can be applied also to other experiments and phenomena.

Structure of χ3-Borophene Studied by Total-Reflection High-Energy Positron Diffraction (TRHEPD)

“…At incident energy E = 10 keV, the critical angle for an Ag crystal with eV 0 = 23 eV is θ C = 2.8 • [2]. Calculations of the rocking curves for TRHEPD were performed by the structure-analysis program, "2DMAT" [21], as well as the one build by Hanada et al [22,23].…”