This readme.txt file was generated on Aug 26 2021 by the Data Repository for the University of Minnesota (DRUM)

Recommended citation for the data:  Zhang, Yichao; Flannigan, David, J. (2021). UEM data supporting "Imaging Nanometer Phonon Softening at Crystal Surface Steps with 4D Ultrafast Electron Microscopy". Retrieved from the Data Repository for the University of Minnesota, https://doi.org/10.13020/qxmn-1t31.


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GENERAL INFORMATION
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1. Title of Dataset:  UEM data supporting "Imaging Nanometer Phonon Softening at Crystal Surface Steps with 4D Ultrafast Electron Microscopy" 

2. Author Information

  Principal Investigator Contact Information
        Name: Yichao Zhang
           Institution: University of Minnesota Ultrafast Electron Microscopy Lab
           Address: Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
           Email: zhan5195@umn.edu
	   ORCID:

  Associate or Co-investigator Contact Information
        Name: David J. Flannigan
           Institution: University of Minnesota Ultrafast Electron Microscopy Lab
           Address: Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
           Email: flan0076@umn.edu
	   ORCID: https://orcid.org/0000-0002-1829-1868


3. Date published: 2021-08-25

4. Date of data collection: 2019-06-01 to 2019-06-01

5. Geographic location of data collection: na

6. Information about funding sources that supported the collection of the data: National Science Foundation under Grant No. DMR-1654318; National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-2011401; Louise T. Dosdall Fellowship

7. Overview of the data (abstract): This dataset includes 4D ultrafast electron microscopy (UEM) bright-field imaging data supporting the paper "Imaging Nanometer Phonon Softening at Crystal Surface Steps with 4D Ultrafast Electron Microscopy".



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SHARING/ACCESS INFORMATION
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1. Licenses/restrictions placed on the data: CC0 1.0 Universal http://creativecommons.org/publicdomain/zero/1.0/

2. Links to publications that cite or use the data: Nano Lett. 2021, 21, 10.1021/acs.nanolett.1c02524, https://doi.org/10.1021/acs.nanolett.1c02524 

3. Related data: Images are used in the video linked from the paper. The video was cropped from a specific specimen region. Video caption: High spatiotemporal-resolution UEM video of phonon dynamics at a step edge in an ultrathin 2H-MoS2 flake (AVI). https://pubs.acs.org/doi/suppl/10.1021/acs.nanolett.1c02524/suppl_file/nl1c02524_si_002.avi 

4. DRUM Terms of Use: By using these files, users agree to the Terms of Use. https://conservancy.umn.edu/pages/drum/policies/#terms-of-use 

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DATA & FILE OVERVIEW
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1. File List
   A. Filename:  Phonon softening UEM data.zip		   
      Short description: UEM data
      Size: 2.222Gb	
      Format: application/zip  

The folder contains images in 724 files in .dm3, .dm4, and .tif format. The naming convention is Run_7_0_image number in obtained order_time point on the delay stage.file format. Noise_4_30s_2.dm3 is the dark reference image. Each image in the folder was subtracted by the reference image before any imaging processing.



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METHODOLOGICAL INFORMATION
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1. Description of methods used for collection/generation of data: 
The data acquisition software creates the images in .dm4, which is a proprietary format. Each image was converted to .dm3 (for further analysis and processing) and .tiff (for easy viewing) files. I use MATLAB to analyze these images. 

2. Methods for processing the data: The images are of a bulk MoS2 crystal. Details of the sample preparation procedure and characterization, as well as the acquisition method are provided in the method section of the paper. 

3. Instrument- or software-specific information needed to interpret the data: The .dm3 and .dm4 files can be opened in Digital Micrograph. The .tiff files can be viewed in typical image viewer softwares.

4. People involved with sample collection, processing, analysis and/or submission: Lisa Zeeb designed a cover image for this paper, included as figure