摘要
In this paper we demonstrated a method to reconstruct vector-valued lattice distortion fields within nanoscale crystals by optimization of a forward model of multi-reflection Bragg coherent diffraction imaging(MR-BCDI)data.The method flexibly accounts for geometric factors that arise when making BCDI measurements,is amenable to efficient inversion with modern optimization toolkits,and allows for globally constraining a single image reconstruction to multiple Bragg peak measurements.This is enabled by a forward model that emulates the multiple Bragg peaks of a MR-BCDI experiment from a single estimate of the 3D crystal sample.We present this forward model,we implement it within the stochastic gradient descent optimization framework,and we demonstrate it with simulated and experimental data of nanocrystals with inhomogeneous internal lattice displacement.We find that utilizing a global optimization approach to MR-BCDI affords a reliable path to convergence of data which is otherwise challenging to reconstruct.
基金
The development of the MR-BCDI forward model and inversion approach,experimental demonstration,and design and fabrication of the SiC nanoparticles was supported by the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences,Materials Science and Engineering Division.Additional support for materials preparation came from the Q-NEXT Quantum Center,a U.S.Department of Energy,Office of Science,National Quantum Information Science Research Center,under Award Number DE-FOA-0002253
Silicon carbide deterministic nanoparticle fabrication and SEM characterization work was performed under proposals 72483 and 775514 in the Center for Nanoscale Materials clean room.Work performed at the Center for Nanoscale Materials,a U.S
Department of Energy Office of Science User Facility,was supported by the U.S.DOE,Office of Basic Energy Sciences,under Contract No.DE-AC02-06CH11357
Refinement of the geometric,computational and optimization concepts was supported by the European Research Council(European Union’s Horizon H2020 research and innovation program grant agreement No.724881).Generation of the simulated structures and the BCDI data acquisition was supported by the Laboratory Directed Research and Development(LDRD)funding from Argonne National Laboratory,provided by the Director,Office of Science,of the U.S.Department of Energy under Contract No.DE-AC02-06CH11357
This research uses the resources of the Advanced Photon Source,a U.S.DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract No.DE-AC02-06CH11357
The authors gratefully acknowledge numerous valuable discussions with Drs.Anthony Rollett,Robert Suter and Matthew Wilkin(Carnegie Mellon University),Nicholas Porter and Dr.Richard Sandberg(Brigham Young University),Dr.Ross Harder(Argonne National Laboratory)and Dr.Anastasios Pateras(DESY).The authors gratefully acknowledge numerous valuable discussions and experimental guidance from Dr.David A.Czaplewski,Suzanne Miller,and Dr.Ralu Divan of the Center of Nanoscale Materials.
