Data from: Discovery of spontaneous mesoscopic strain waves in nematic domains using dark-field X-ray microscopy
Data files
Apr 09, 2026 version files 107.53 MB
-
README.md
4.10 KB
-
StrainWavesManuscript_data.zip
107.52 MB
Abstract
Electronic nematic order arises when correlated electrons spontaneously break the rotational symmetry of a crystal lattice. When electronic nematic order couples bilinearly to symmetry-breaking lattice strain, both appear together at a single ferroelastic phase transition, producing structural twin domains with distinct orientations of the nematic director. While the effects of applied strain on these domains are well established, the intrinsic behavior of spontaneous subdomain strain fields has remained unexplored. Here, we report the discovery of spontaneous mesoscopic strain waves within individual nematic domains of an iron-based superconductor, observed using dark-field X-ray microscopy (DFXM). Using this novel full-field imaging technique, we visualize subdomain strain modulations emerging concurrently with nematic order. Elastic compatibility relations governing inhomogeneous strains provide a natural mechanism for the strain waves. Our findings reveal a broadly relevant form of strain self-organization and position DFXM as a powerful probe of the local interplay between lattice strain and electronic order.
File name: StrainWavesManuscript_data.zip
Created by: Kaan Alp Yay, Stanford University
Email: kaanalpyay@stanford.edu
Creation date: 15-Sep-25
Last edited: 08-Apr-26
Description
This repository contains data files corresponding to each figure in the manuscript that includes experimental data.
- Microscopy images are provided in
.npz(NumPy container),.h5(HDF5), and.tiffformats to ensure compatibility with different programming languages. - Line plot data (Fig. 3b – lower panel) is provided in
.csvand.npzformats.
Image details
- For microscopy images (Figures 2b, 3a, 3b upper panel, 3c, 4a, 4b):
- Each pixel corresponds to 50 nm × 50 nm. (nm = nanometers)
- NaN values in strain and orientation maps represent regions with insufficient X-ray intensity.
- For Fourier transform images (Figure 4c):
- Each pixel corresponds to approximately 0.00927 μm⁻¹ × 0.00927 μm⁻¹. (μm⁻¹ = inverse microns)
Data file list
- Fig1c_up.h5, .npz, .tiff – Fig. 1c upper panel
- The 220 reflection of Ba(Fe0.98Cu0.02)2As2 (Cu-Ba122) in the tetragonal phase at 100 K (Kelvin), measured by high-energy X-ray diffraction. Each array element is a raw detector pixel, and the contained number value is X-ray diffraction intensity in arbitrary units.
- Fig1c_lp.h5, .npz, .tiff – Fig. 1c lower panel
- Fully split 220 peak at base temperature 𝑇 = 10 K. Units are the same as in the upper panel.
- Fig2b_lp.h5, .npz, .tiff – Fig. 2b lower panel
- Real-space microscope image of the 0401 peak at 60 K. Each pixel corresponds to 50 nm × 50 nm, and the contained value is X-ray diffraction intensity in arbitrary units.
- Fig2b_up.h5, .npz, .tiff – Fig. 2b upper panel
- Real-space microscope image of the 4004 peak at 3 K. Units are the same as in the lower panel.
- Fig3a.h5, .npz, .tiff – Fig. 3a
- Real-space strain map of a nematic domain scattering at the 0401 peak at 80 K. Each pixel corresponds to 50 nm × 50 nm, and the contained value is the strain deviation from the median d-spacing value of the domain in units of 10-5.
- Fig3b_up.h5, .npz, .tiff – Fig. 3b upper panel
- Zoomed in cutout of Fig. 3a but with the x and y axes rotated counterclockwise by 45 degrees. Units are the same as ing Fig. 3a.
- Fig3b_lp.csv, .npz – Fig. 3b lower panel
- Values of Fig. 3b upper panel averaged along the y axis of the array. Each line item is separated in space by 50 nm and the values correspond to the strain deviation from the median d-spacing value of the domain in units of 10-5.
- Fig3c.h5, .npz, .tiff – Fig. 3c
- Real-space strain map of the 220 peak at 100 K. Each pixel corresponds to 50 nm × 50 nm, and the contained value is the strain deviation from the median d-spacing value of the domain in units of 10-5.
- Fig4a.h5, .npz, .tiff – Fig. 4a
- Real-space orientation map of (400)4 lattice planes. Each pixel corresponds to 50 nm × 50 nm, and the contained value is the center of mass θ value for a given pixel.
- Fig4b.h5, .npz, .tiff – Fig. 4b
- Real-space scattering intensity map at a particular lattice orientation value θ. Each pixel corresponds to 50 nm × 50 nm, and the contained value is X-ray diffraction intensity in arbitrary units.
- Fig4c_center.h5, .npz, .tiff – Fig. 4c center panel
- Fourier transform of microscope images of the 0401 peak at 80 K. Each pixel value is log intensity in arbitrary units.
- Fig4c_left.h5, .npz, .tiff – Fig. 4c left panel
- Fourier transform of microscope images of the 0401 peak at 60 K. Each pixel value is log intensity in arbitrary units.
- Fig4c_right.h5, .npz, .tiff – Fig. 4c right panel
- Fourier transform of microscope images of the 4004 peak at 3 K. Each pixel value is log intensity in arbitrary units.