We present low‐temperature X‐ray fluorescence holography experiments to investigate the atomic scale structure of the high‐temperature superconductor FeSe0.4Te0.6. The results present a direct investigation of the local structure around the Fe atoms. Very clear images of the structure are obtained by a sparse modeling approach to the experimental data using a L1‐regularized linear regression. The results are in good agreement with previous findings of XRD and XAFS experiments on the FeSe1−xTex system, but furthermore indicate large fluctuations in the Fe sub‐lattice. The findings also represent a starting point for further discussions on more curious features of the FeSe1−xTex structure.

To observe the difference of atomic heights between the Se and Te layers with respect to the Fe layer in FeSe