Abstract

X-ray absorption spectroscopy (XAS) produces a wealth of information about the local structure of materials, but interpretation of spectra often relies on easily accessible trends and prior assumptions about the structure. Recently, researchers have demonstrated that machine learning models can automate this process to predict the coordinating environments of absorbing atoms from their XAS spectra. However, machine learning models are often difficult to interpret, making it challenging to determine when they are valid and whether they are consistent with physical theories. In this work, we present three main advances to the data-driven analysis of XAS spectra: we demonstrate the efficacy of random forests in solving two new property determination tasks (predicting Bader charge and mean nearest neighbor distance), we address how choices in data representation affect model interpretability and accuracy, and we show that multiscale featurization can elucidate the regions and trends in spectra that encode various local properties. The multiscale featurization transforms the spectrum into a vector of polynomial-fit features, and is contrasted with the commonly-used “pointwise” featurization that directly uses the entire spectrum as input. We find that across thousands of transition metal oxide spectra, the relative importance of features describing the curvature of the spectrum can be localized to individual energy ranges, and we can separate the importance of constant, linear, quadratic, and cubic trends, as well as the white line energy. This work has the potential to assist rigorous theoretical interpretations, expedite experimental data collection, and automate analysis of XAS spectra, thus accelerating the discovery of new functional materials.

Details

Title
Random forest machine learning models for interpretable X-ray absorption near-edge structure spectrum-property relationships
Author
Torrisi, Steven B 1   VIAFID ORCID Logo  ; Carbone, Matthew R 2   VIAFID ORCID Logo  ; Rohr, Brian A 3 ; Montoya, Joseph H 3 ; Yang, Ha 4 ; Yano Junko 5 ; Suram, Santosh K 6   VIAFID ORCID Logo  ; Hung, Linda 6   VIAFID ORCID Logo 

 Toyota Research Institute, Accelerated Materials Design and Discovery, Los Altos, USA; Harvard University, Department of Physics, Cambridge, USA (GRID:grid.38142.3c) (ISNI:000000041936754X) 
 Columbia University, Department of Chemistry, New York, USA (GRID:grid.21729.3f) (ISNI:0000000419368729) 
 Toyota Research Institute, Accelerated Materials Design and Discovery, Los Altos, USA (GRID:grid.21729.3f) 
 Lawrence Berkeley National Laboratory, Advanced Light Source, Berkeley, USA (GRID:grid.184769.5) (ISNI:0000 0001 2231 4551) 
 Lawrence Berkeley National Laboratory, Molecular Biophysics and Integrated Bioimaging Division, Berkeley, USA (GRID:grid.184769.5) (ISNI:0000 0001 2231 4551) 
 Toyota Research Institute, Accelerated Materials Design and Discovery, Los Altos, USA (GRID:grid.184769.5) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
20573960
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2428276744
Copyright
© The Author(s) 2020. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.