Ultramicroscopy最新文献

An unbiased ADMM-TGV algorithm for the deconvolution of STEM-EELS maps STEM-EELS图反卷积的无偏ADMM-TGV算法

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-16 DOI: 10.1016/j.ultramic.2025.114159

Christian Zietlow, Jörg K.N. Lindner

{"title":"An unbiased ADMM-TGV algorithm for the deconvolution of STEM-EELS maps","authors":"Christian Zietlow, Jörg K.N. Lindner","doi":"10.1016/j.ultramic.2025.114159","DOIUrl":"10.1016/j.ultramic.2025.114159","url":null,"abstract":"<div><div>Electron-energy-loss-spectroscopy (EELS) spectra in the scanning transmission electron microscope (STEM) are affected by various types of noise. Additionally, they are convolved with the detector point spread function and the energy distribution of the electron source. Often, iterative deconvolution is employed to sharpen peaks and improve the data. However, since the Richardson–Lucy algorithm (RLA) has become the standard deconvolution algorithm in EELS, little progress has been made in terms of technique. In this paper, the authors aim to provide an update to STEM-EELS deconvolution and demonstrate how to significantly improve results compared to those achievable with the RLA. The major limitation of the RLA is that it does not guarantee convergence. Furthermore, the RLA is restricted to pure Poisson noise and lacks adaptability due to limitations in its general structure, particularly when compared to more modern algorithms. A new and versatile approach is the Alternating Direction Method of Multipliers (ADMM), which is based on Lagrangian methods and enables to overcome these restrictions. The generality of ADMM allows us to develop a deconvolution algorithm tailored to EELS maps and incorporate a recent noise model. We extend the standard Bayesian maximum likelihood of the RLA to a maximum a-posteriori approach in ADMM, which enables us to leverage the principles of total general variation (TGV) to enforce convergence. Furthermore, we define the algorithm such that it operates unbiased of the user. To demonstrate the superiority of the ADMM, it is tested against the RLA using simulated data. Eventually, our algorithm is successfully applied to experimental data as well.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"275 ","pages":"Article 114159"},"PeriodicalIF":2.1,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144088772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Laser-driven cold field emission source for ultrafast transmission electron microscopy 超快透射电镜用激光驱动冷场发射源

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-14 DOI: 10.1016/j.ultramic.2025.114158

Alexander Schröder , Andreas Wendeln , Jonathan T. Weber , Masaki Mukai , Yuji Kohno , Sascha Schäfer

{"title":"Laser-driven cold field emission source for ultrafast transmission electron microscopy","authors":"Alexander Schröder , Andreas Wendeln , Jonathan T. Weber , Masaki Mukai , Yuji Kohno , Sascha Schäfer","doi":"10.1016/j.ultramic.2025.114158","DOIUrl":"10.1016/j.ultramic.2025.114158","url":null,"abstract":"<div><div>Ultrafast transmission electron microscopy (UTEM) has emerged as a versatile technique for the time-resolved imaging of nanoscale dynamics on timescales down to few-hundred attoseconds but the temporal and spatial resolutions are still limited by the coherence properties of pulsed electron sources. Here, we report the development of a novel laser-driven linear cold field electron emitter integrated in a state-of-the-art UTEM system. Tuning the emitter’s workfunction via an applied extraction field and illuminating the sharp tungsten emitter tip with UV light pulses generates ultrashort femtosecond electron pulses of 220 fs pulse duration at 200 keV electron energy, with energy widths as low as 360 meV. The photoelectron emitter demonstrates exceptional spatial coherence, achieving focal spot sizes down to 2 Å and a peak normalized brightness exceeding 6.7 <span><math><mrow><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>13</mn></mrow></msup></mrow></math></span> A/m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>sr. With an order-of-magnitude improvement compared to previously employed laser-driven Schottky field emitters, the present development opens up the field of ultrafast atomic-scale electron probing.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"275 ","pages":"Article 114158"},"PeriodicalIF":2.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Data-driven control in atomic force microscopy using a genetic algorithm 使用遗传算法的原子力显微镜数据驱动控制

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-14 DOI: 10.1016/j.ultramic.2025.114156

Navid Asmari , Lukas Neuner , Richard Weiss , Amin Mazloumian , Matthias Rosenthal , Alireza Karimi , Georg Ernest Fantner

引用次数: 0

Quantitative magnetic mapping in TEM through accurate 2D thickness determination 通过精确的二维厚度测定，在TEM中进行定量磁成像

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-09 DOI: 10.1016/j.ultramic.2025.114140

Joseph Vimal Vas , Hasan Ali , Wen Shi , Thibaud Denneulin , Ayush K Gupta , Rohit Medwal , Rafal E. Dunin-Borkowski

{"title":"Quantitative magnetic mapping in TEM through accurate 2D thickness determination","authors":"Joseph Vimal Vas , Hasan Ali , Wen Shi , Thibaud Denneulin , Ayush K Gupta , Rohit Medwal , Rafal E. Dunin-Borkowski","doi":"10.1016/j.ultramic.2025.114140","DOIUrl":"10.1016/j.ultramic.2025.114140","url":null,"abstract":"<div><div>Off-axis Electron Holography and Electron Magnetic Circular Dichroism are powerful Transmission Electron Microscopy (TEM) techniques capable of mapping magnetic information with near-atomic spatial resolution. However, the magnetic signals obtained is semi-quantitative due to factors such as thickness variations and local crystallographic changes. Precise determination of spatial thickness variations can make these techniques more quantitative. Electron Energy Loss Spectroscopy (EELS) provides a method to measure thickness variations within a region of interest. The absolute thickness depends on reliable estimates of the inelastic mean free path (<span><math><mi>λ</mi></math></span>), which is often unknown for many materials. Alternative techniques, such as Scanning Electron Microscopy (SEM) and Convergent Beam Electron Diffraction (CBED), either lack spatial resolution in thickness mapping or are accurate only within a limited thickness range. Here, we present a straightforward approach to precisely determine the inelastic mean free path (<span><math><mi>λ</mi></math></span>), enabling accurate thickness measurements from EELS maps. We compare these thickness measurements with CBED- and SEM-based methods, identifying discrepancies, particularly in thinner samples (<span><math><mrow><mo><</mo><mn>100</mn><mspace></mspace><mi>nm</mi></mrow></math></span>). Finally, we demonstrate how this calibrated thickness measurement can provide quantitative magnetic maps using TEM-based magnetic measurements.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"275 ","pages":"Article 114140"},"PeriodicalIF":2.1,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An improved soft-thresholding exit wave reconstruction for imaging beam-sensitive materials 一种用于光束敏感材料成像的改进软阈值出口波重建方法

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-04 DOI: 10.1016/j.ultramic.2025.114154

Hongsheng Shi , Yuan Lu , Zeyu Wang , Shuchen Zhang , Yi Yu

{"title":"An improved soft-thresholding exit wave reconstruction for imaging beam-sensitive materials","authors":"Hongsheng Shi , Yuan Lu , Zeyu Wang , Shuchen Zhang , Yi Yu","doi":"10.1016/j.ultramic.2025.114154","DOIUrl":"10.1016/j.ultramic.2025.114154","url":null,"abstract":"<div><div>High-resolution transmission electron microscopy (HRTEM) is a widely-used technique for atomic-scale characterization. However, the conventional dose of HRTEM can destroy beam-sensitive materials such as organic-inorganic halide perovskites. CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> (MAPbI<sub>3</sub>), a typical perovskite, will be easily damaged after irradiated with the dose of ∼10<sup>2</sup> e-/Å<sup>2</sup>. Low-dose imaging techniques can protect the specimen but it is difficult to achieve an image which is both directly interpreted and atomically clear. Exit wave reconstruction (EWR), as one of phase retrieval methods, can recover an interpretable phase image at the atomic scale but its signal-to-noise ratio (SNR) is limited by low electron doses. Here, we improve the iterative wave function reconstruction (IWFR) method and present a soft-thresholding L<sub>1</sub>-IWFR. Results from both simulated and experimental focal-series dataset at the extremely low dose show that L<sub>1</sub>-IWFR improves the SNR effectively and has better performance on low-dose datasets than IWFR. Combined with low-dose imaging techniques and various alignment strategies, an atomically clear image of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> (MAPbI<sub>3</sub>) is successfully achieved at the total dose of ∼45 e<sup>-</sup>/Å<sup>2</sup>.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"274 ","pages":"Article 114154"},"PeriodicalIF":2.1,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Compact design, construction, and evaluation of an in situ ±90° rotatable magnetic force microscope in a 12 T superconducting magnet 在12 T超导磁体上的原位±90°可旋转磁力显微镜的紧凑设计，构建和评估

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-03 DOI: 10.1016/j.ultramic.2025.114155

Min Zhang , Shuai Dong , Zihao Li , Kesen Zhao , Aile Wang , Wenjie Meng , Qiyuan Feng , Jing Zhang , Jihao Wang , Yalin Lu , Yubin Hou , Qingyou Lu

{"title":"Compact design, construction, and evaluation of an in situ ±90° rotatable magnetic force microscope in a 12 T superconducting magnet","authors":"Min Zhang , Shuai Dong , Zihao Li , Kesen Zhao , Aile Wang , Wenjie Meng , Qiyuan Feng , Jing Zhang , Jihao Wang , Yalin Lu , Yubin Hou , Qingyou Lu","doi":"10.1016/j.ultramic.2025.114155","DOIUrl":"10.1016/j.ultramic.2025.114155","url":null,"abstract":"<div><div>Cryogenic magnetic force microscopy (MFM) is a powerful technique capable of resolving exotic magnetic textures with nanoscale resolution in real-space. We introduce a cryogenic rotatable MFM (CRMFM) that enables the visualization of in situ evolution of magnetic domains by rotating magnetic samples between −90° and +90° within a 12 T superconducting magnet. By continuously rotating the sample under an external magnetic field, the direction of the magnetic field can be varied from out-of-plane to in-plane, enabling microscopic analysis experiments that require vector magnetic fields within the CRMFM system. By using CRMFM measurements, we successfully transformed long magnetic stripe domains into isolated magnetic bubble domains and proposed a novel strategy for visualizing stripe-bubble transitions in magnetic domains. Additionally, we demonstrated that the CRMFM system can generate high-quality MFM images under in-plane magnetic fields up to 12 T. Our research provides a framework for visualizing the interaction between ferromagnetism and magnetic field direction, facilitating the study of magnetic crystal anisotropy.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"274 ","pages":"Article 114155"},"PeriodicalIF":2.1,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-precision atomic imaging using an innovative vibration-isolated scanning tunneling microscope 使用创新的隔振扫描隧道显微镜进行高精度原子成像

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-03 DOI: 10.1016/j.ultramic.2025.114157

Behnam Esmaeilzadeh , Muhammad Touqeer , Syed Asad Maqbool , Jihao Wang , Wenjie Meng , Yubin Hou , Yalin Lu , Qingyou Lu

{"title":"High-precision atomic imaging using an innovative vibration-isolated scanning tunneling microscope","authors":"Behnam Esmaeilzadeh , Muhammad Touqeer , Syed Asad Maqbool , Jihao Wang , Wenjie Meng , Yubin Hou , Yalin Lu , Qingyou Lu","doi":"10.1016/j.ultramic.2025.114157","DOIUrl":"10.1016/j.ultramic.2025.114157","url":null,"abstract":"<div><div>The stability of the scanning unit in a scanning tunneling microscope (STM) is essential for achieving high-resolution imaging. In this study, we present a non-metallic STM with a mechanically isolated scanning unit, ensuring long-term drift stability, low backlash, and high repeatability. By decoupling the piezoelectric scanning tube (PST) from the piezoelectric motor tube (PMT), the design effectively minimizes motor-induced instabilities and vibrations, significantly improving STM performance. The use of non-metallic materials for key components prevents eddy current interference and ensures long-term reliability. A sapphire-based frame provides high stiffness and compactness, with an eigenfrequency of 16.2 kHz in bending mode, reducing vibration noise during atomic imaging. The system exhibits excellent stability, maintaining low drift rates in both the X-Y plane and Z direction, ensuring precise tip-sample alignment. The performance of the home-built STM was validated through high-resolution atomic imaging of graphite and TaS<sub>2</sub> surfaces. The simple, compact, and high-precision stepping mechanism, along with its ability to operate at low voltage, reduces experimental complexity. These features facilitate advanced material studies in constrained environments, such as high magnetic fields and low temperatures.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"274 ","pages":"Article 114157"},"PeriodicalIF":2.1,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Prediction of the morphology of nano particles based solely on atom counting data 仅基于原子计数数据的纳米粒子形态预测

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-05-02 DOI: 10.1016/j.ultramic.2025.114139

Ivo Alxneit

{"title":"Prediction of the morphology of nano particles based solely on atom counting data","authors":"Ivo Alxneit","doi":"10.1016/j.ultramic.2025.114139","DOIUrl":"10.1016/j.ultramic.2025.114139","url":null,"abstract":"<div><div>The framework to determine the morphology of nano particles from atomically resolved electron microscopy images and atom counting data is introduced. Focus is placed on electron microscopy data avoiding advanced geometry optimization of the particle. The problem is solved by simulated annealing with different fitness functions assessed. Even for small particles the solution space rapidly becomes too large to be exhausted. The concept of site occupation probabilities, <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>, is then used to analyze a subset, typically very few hundred solutions. This is shown to be sufficient to reach a relative error of below 10% for <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>></mo><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math></span> already with 100 solutions allowing to determine with high confidence and low statistical error realistic average shapes also for nano particles of a few thousand atoms. These particles typically exhibit a well defined core covered by a layer of sites that are not occupied in each solution. It is further demonstrated that sites with high probability to contain a vacancy can be identified <em>assuming</em> the presence of a vacancy. If a vacancy is actually present in a particle its position can be identified with rather high fidelity. Finally, it is shown that the procedure can cope with the statistical error or ambiguities inherent in atom counting data based on noisy, low dose electron microscopy images.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"275 ","pages":"Article 114139"},"PeriodicalIF":2.1,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144123527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Robust projection parameter calibration in cryo-ET with L1-norm optimization 基于l1范数优化的cryo-ET鲁棒投影参数标定

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-04-29 DOI: 10.1016/j.ultramic.2025.114134

Shengkai Guo , Zihe Xu , Xinyan Li , Zhidong Yang , Chenjie Feng , Renmin Han

{"title":"Robust projection parameter calibration in cryo-ET with L1-norm optimization","authors":"Shengkai Guo , Zihe Xu , Xinyan Li , Zhidong Yang , Chenjie Feng , Renmin Han","doi":"10.1016/j.ultramic.2025.114134","DOIUrl":"10.1016/j.ultramic.2025.114134","url":null,"abstract":"<div><div>Fiducial marker-based alignment in cryo-electron tomography (cryo-ET) has been extensively studied over a long period. The calibration of projection parameters using nonlinear least squares technique methodologies stands as the ultimate and pivotal stage in the alignment procedure. The efficacy of calibration is substantially impacted by noise and outliers in the marker data obtained from previous steps. Several robust fitting methods have been explored and implemented to address this issue by improving marker data or assigning weights to markers. However, these methods have their own limitations and often assume general Gaussian noise assumption, which may not accurately represent the distribution of noise and outliers in the marker data. In this work, we propose a robust projection parameter calibration model based on <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>-norm optimization under Laplace noise assumption in order to overcome the limitations of existing methods. To efficiently solve the problem, we also design a faster and stabler first-order non-sparse method based on smooth approximation strategy. Additionally, we introduce subgradient and subdifferential for mathematical analysis. The accuracy, robustness, and efficacy of our approach are demonstrated through both simulated and real-world experiments.</div></div>","PeriodicalId":23439,"journal":{"name":"Ultramicroscopy","volume":"274 ","pages":"Article 114134"},"PeriodicalIF":2.1,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143907639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the impulse approximation in electron Compton scattering 电子康普顿散射中的脉冲近似

IF 2.1 3区工程技术

Ultramicroscopy Pub Date : 2025-04-26 DOI: 10.1016/j.ultramic.2025.114153

BG Mendis

引用次数: 0